I considered all the living which walk under the sun, with the second child that shall stand up in his stead.

I saw all the living that walk under the sun, that they were with the youth, the second, that stood up in his stead.

I saw all men living, that walk under the sun with the second young man, who shall rise up in his place.

I saw all the living that walk under the sun, with the child, the second, that should stand up in his stead.

I have seen all the living, who are walking under the sun, with the second youth who doth stand in his place;

I saw all the living under the sun round the young man who was to be ruler in place of the king.

I saw all the living who are walking under the sun, and I saw the next generation, who shall rise up in their places.

I considered - literally, I saw "all the population of the young man's kingdom."
The second child - This second youth is generally understood to be identical with the one mentioned in Ecclesiastes 4:13.

With the second child that shall stand up - The Targum applies this to the case of Jeroboam and Rehoboam. History affords many instances of mean persons raised to sovereign authority, and of kings being reduced to the meanest offices, and to a morsel of bread. Agrippa himself ascended the throne of Israel after having been long in prison. See Josephus, Ant. lib. 18: c. 8. This the heathens attributed to fortune.
Si fortuna volet, fies de rhetore consul;
Si volet haec eadem, fies de consule rhetor.
Juv. Sat. vii., ver. 197.
Though I have given what the Jews suppose to be the allusion in these verses, yet the reader may doubt whether the reference be correct. There is a case implied, whether from fact or assumption I cannot say; but it seems to be this:
A king who had abused the authority vested in him by oppressing the people, had a son whose prudent conduct promised much comfort to the nation, when he should come to the throne. The father, seeing the popular wish, and becoming jealous of his son, shut him up in prison. In the interim the old king either dies or is deposed, and the son is brought out of prison, and placed on the throne. Then (Ecclesiastes 4:15, Ecclesiastes 4:16) multitudes of the people flock to him, and begin to walk under the sun; i.e., the prosperous state to which the nation is raised by its redemption from the former tyranny. However, the wise man insinuates that this sunshine will not last long. The young king, feeling the reins in his own hands, and being surrounded by those whose interest it was to flatter in order to obtain and continue in court favor, he also becomes corrupted so that those who come after shall have no cause of rejoicing in him. This appears to be the case; and similar cases have frequently occurred, not only in Asiatic, but also in European history, I have, in another place, referred to the case of Rushn Achter, who was brought out of prison and set upon the throne of Hindoostan. This is expressed in the following elegant Persian couplet, where his fortune is represented as similar to that of the patriarch Joseph: -
"The bright star is now become a moon:
Joseph is taken out of prison, and become a king."
Rushn Achter signifies a bright or splendid star.

I considered all the living who walk under the sun, (k) with the second child that shall stand up in his stead.
(k) Who follow and flatter the king's son, or him that will succeed to enter into credit with them in hope of gain.

I considered all the living which walk under the sun,.... All men that were then alive, who were capable of walking upon the earth; even all of them that were under the heavens, in every land and nation, under whatsoever dominion or government: these, and their manners, Solomon had particularly observed, and made his remarks upon, by which it appeared how fickle the minds of the populace were under every government, and how precarious and uncertain were the honour and dignity of princes;
with the second child that shall stand up in his stead: the heir and successor or every prince, that shall rise up and take the throne of his father or predecessor, and reign in his stead. The wise man observed how the people commonly behaved towards him; how that they generally stood best affected to him, than to the reigning prince; worshipped the rising sun, courted his favour and friendship, soothed and flattered him; expressing their wishes to see him on the throne, and treated with neglect and contempt their lawful sovereign. Some, contrary to the accents, connect this with the word "walk" (h); that walk with the second child, join themselves to him, converse with him, and show him great respect and honour: and there are others that, by this second child, understand the poor and wise child, that succeeds the old and foolish king, whom yet, in time, the people grow weary of; such is the levity and inconstancy of people, that they are not long pleased with princes, old or young, wise or foolish. The Targum interprets this of the foresight Solomon had, by a spirit of prophecy, of those that rebelled against his son Rehoboam, and of those that cleaved unto him, who was his second, and reigned in his stead. Noldius (i) thinks Solomon refers to the history of his friend Hiram, king of Tyre, whose kingdom, in his and in his son's time, was very large, flourishing, and opulent, but in a following reign not so; and he renders and paraphrases the words thus,
""I saw all the works under the sun; with Baleazarus, the son of a friend" (Hiram, for rendered "second", is the same as "a friend"), "who shall stand" or "reign after him: there is no end of all the people",'' &c.
the kingdom in those two reigns being flourishing; yet posterity shall not rejoice in him, in Abdastratus, the grandson of Hiram, destroyed by the four sons of his nurse (k).
(h) So the Tigurine version, Vatablus, Cocceius, Gejerus. (i) Concord. Part. Ebr. No. 1023. (k) Meander apud Joseph. Contr. Apion. l. 1. s. 18.

"I considered all the living," the present generation, in relation to ("with") the "second youth" (the "legitimate successor" of the "old king," as opposed to the "poor youth," the one first spoken of, about to be raised from poverty to a throne), that is, Rehoboam.
in his stead--the old king's.

"I saw all the living which walk under the sun on the side of the youth, the second who shall enter upon the place of the former: no end of all the people, all those at whose head he stands." The author, by the expression "I saw," places himself back in the time of the change of government. If we suppose that he represents this to himself in a lively manner, then the words are to be translated: of the second who shall be his successor; but if we suppose that he seeks to express from the standpoint of the past that which, lying farther back in the past, was now for the first time future, then the future represents the time to come in the past, as at 2-Kings 3:27; Psalm 78:6; Job 15:28 (Hitz.): of the second who should enter on his place (עמד, to step to, to step forth, of the new king, Daniel 8:23; Daniel 11:2.; cf. קוּם, 1-Kings 8:20). The designation of the crowd which, as the pregnant עם expresses, gathered by the side of the young successor to the old king, by "all the living, those walking under the sun (המה, perhaps intentionally the pathetic word for הלכים, Isaiah 42; 5)," would remain a hyperbole, even although the throne of the Asiatic world-ruler had been intended; still the expression, so absolute in its universality, would in that case be more natural (vid., the conjectural reference to Cyrus and Astygates). השּׁני, Ewald refers to the successor to the king, the second after the king, and translates: "to the second man who should reign in his stead;" but the second man in this sense has certainly never been the child of fortune; one must then think of Joseph, who, however, remains the second man. Hitzig rightly: "The youth is the second שׁני, not אחר, in contrast to the king, who, as his predecessor, is the first." "Yet," he continues, "הילד should be the appos. and השׁני the principal word," i.e., instead of: with the second youth, was to be expected: with the second, the youth. It is true, we may either translate: with the second youth, or: with the second, the youth - the_ form of expression has in its something incorrect, for it has the appearance as if it treated of two youths. But similar are the expressions, Matthew 8:21, ἓτερος κ.τ.λ., "another, and that, too, one of His disciples;" and Luke 23:32, ἤγοντο κ.τ.λ All the world ranks itself by the side (thus we may also express it) of the second youthful king, so that he comes to stand at the head of an endless multitude. The lxx, Jerome, and the Venet. render incorrectly the all (the multitude) as the subject of the relative clause, which Luther, after the Syr., corrects by reading לפניו for לפניהם: of the people that went for him there was no end. Rightly the Targ.: at whose head (= בּרישׁיהון) he had the direction, לפני, as with יצא ובא, 1-Samuel 18:16; 2-Chronicles 1:10; Psalm 68:8, etc. All the world congregates about him, follows his leadership; but his history thus splendidly begun, viewed backwards, is a history of hopes falsified.
"And yet they who come after do not rejoice in him: for that also is vain, and a grasping after the wind." For all that, and in spite of that (gam has here this meaning, as at Ecclesiastes 6:7; Jeremiah 6:15; Psalm 129:2; Ewald, 354a), posterity (הא, as at Ecclesiastes 1:11; cf. Isaiah 41:4) has no joy in this king, - the hopes which his contemporaries placed in the young king, who had seized the throne and conquered their hearts, afterwards proved to be delusions; and also this history, at first so beautiful, and afterwards so hateful, contributed finally to the confirmation of the truth, that all under the sun is vain. As to the historical reminiscence from the time of the Ptolemies, in conformity with which Hitzig (in his Comm.) thinks this figure is constructed; Grtz here, as always, rocks himself in Herodian dreams. In his Comm., Hitz. guesses first of Jeroboam, along with Rehoboam the שׁני ילד, who rebelled against King Solomon, who in his old age had become foolish. In an essay, "Zur Exeg. u. Kritik des B. Koheleth," in Hilgenfeld's Zeitschr. XIV 566ff., Saul, on the contrary, appears to him to be the old and foolish king, and David the poor wise youth who rose to the throne, and took possession of the whole kingdom, but in his latter days experienced desertion and adversities; for those who came after (the younger men) had no delight in him, but rebelled against him. But in relation to Saul, who came from the plough to be king, David, who was called from being a shepherd, is not נולד רשׁ; and to Jewish history this Saul, whose nobler self is darkened by melancholy, but again brightens forth, and who to his death maintained the dignity of a king of Israel, never at any time appears as וכסיל מלך. Moreover, by both combinations of that which is related with the הסורים בּית (for which הסּ is written) of the history of the old Israelitish kings, a meaning contrary to the usage of the language must be extracted. It is true that סוּר, as the so-called particip. perfecti, may mean "gone aside (to a distance)," Isaiah 49:21; Jeremiah 17:13; and we may, at any rate, by סורים, think on that poor rabble which at first gathered around David, 1-Samuel 22:2, regarded as outcasts from honourable society. But בית will not accord therewith. That David came forth from the house (home) of the estranged or separated, is and remains historically an awkward expression, linguistically obscure, and not in accordance with the style of Koheleth. In order to avoid this incongruity, Bttcher regards Antiochus the Great as the original of the ילד. He was the second son of his father, who died 225. When a hopeful youth of fifteen years of age, he was recalled to the throne from a voluntary banishment into Farther Asia, very soon gained against his old cousin and rival Achaeus, who was supported by Egypt, a large party, and remained for several years esteemed as a prince and captain; he disappointed, however, at a later time, the confidence which was reposed in him. But granting that the voluntary exile of Antiochus might be designated as האס בית, he was yet not a poor man, born poor, but was the son of King Seleucus Callincus; and his older relative and rival Achaeus wished indeed to become king, but never attained unto it. Hence השׁני is not the youth as second son of his father, but as second on the throne, in relation to the dethroned king reckoned as the first. Thus, far from making it probable that the Book of Koheleth originated in the time of the Diadochs, this combination of Bttcher's also stands on a feeble foundation, and falls in ruins when assailed.
The section Eccl 1:12-4:16, to which we have prefixed the superscription, "Koheleth's Experiences and their Results," has now reached its termination, and here for the first time we meet with a characteristic peculiarity in the composition of the book: the narrative sections, in which Koheleth, on the ground of his own experiences and observations, registers the vanities of earthly life, terminate in series of proverbs in which the I of the preacher retires behind the objectivity of the exhortations, rules, and principles obtained from experience, here recorded. The first of these series of proverbs which here follows is the briefest, but also the most complete in internal connection.

I considered - The general disposition of common people, in all kingdoms, that they are fickle and inconstant. With the second child - This may be understood of the king's child, or son and heir, called second, in respect of his father, whose successor he is. Stand up - Arise to reign.