The lines [1] have fallen to me. The Psalmist confirms more fully what he had already said in the preceding verse with respect to his resting, with a composed and tranquil mind, in God alone; or rather, he so glories in God as nobly to despise all that the world imagines to be excellent and desirable without him. By magnifying God in such honorable and exalted strains, he gives us to understand that he does not desire any thing more as his portion and felicity. This doctrine may be profitable to us in many ways. It ought to draw us away not only from all the perverse inventions of superstition, but also from all the allurements of the flesh and of the world. Whenever, therefore, those things present themselves to us which would lead us away from resting in God alone, let us make use of this sentiment as an antidote against them, that we have sufficient cause for being contented, since he who has in himself an absolute fullness of all good has given himself to be enjoyed by us. In this way we will experience our condition to be always pleasant and comfortable; for he who has God as his portion is destitute of nothing which is requisite to constitute a happy life.

Footnotes

1 - The Hebrew is measuring lines. There is here an allusion to the ancient division of the land of Canaan among God's chosen people. This was done by lot, and the length and breadth of the portion of each tribe was ascertained by cords or measuring lines. Hence they came to signify the land so measured out.

The lines - The word used here refers to the "lines" employed in measuring and dividing land, Amos 7:17; 2-Samuel 8:2. Hence, the word comes to denote a portion of land that is "measured out" (or that is "surveyed off") to anyone - his possession or property; and hence, the word refers to the condition in life. The meaning here is, that in running out such a survey, "his" inheritance had been fixed in a pleasant and desirable part of the land.
Are fallen unto me - Referring to the appropriation of the different parts of the land by lot. The idea is, that the land was surveyed into distinct portions, and then that the part which fell to anyone was determined by lot. This was actually the case in distributing the land of Canaan, Numbers 26:55; Numbers 33:54; Numbers 36:2; Josh. 15-19.
In pleasant places - In a pleasant or desirable part of the land.
Yea, I have a goodly heritage - A good, a desirable inheritance. The meaning is, that he regarded it as a desirable heritage that he lived where the true God was known; where he enjoyed his favor and friendship.

The lines are fallen unto me in pleasant places - Here is an allusion to the ancient division of the land by lot among the Israelites, the breadth and length being ascertained by lines which were used in measuring. I have got a rich inheritance of immortal spirits; and I myself, as man, shall have a name above every name, and be raised to thy throne, on which I shall sit, and be admired in my saints to all eternity.
I have a goodly heritage - A Church, an innumerable multitude of saints, partakers of the Divine nature, and filled with all the fullness of God. And these shall dwell with me in the heaven of heavens to all eternity. The old Psalter: -
Psalm 16:5 Dominus pars hereditatis mee et calicis mei, etc.
Trans. Lord es part of myn herytage and of my chalyce; thow ert that sal restore myn herytage til me.
Par - Lord the fader es part, that es, he es porcioun and mede of myn herytage; that es of haly men, qwam I weld in herytage. Other men cheses tham what tham lyst: my part es God, and he es part of my chalyce: that es, he es my copp of al my delyte and boor. Wereldys men drynkes the venemus lustes, and the drubly delytes of lychery and covatys: I in my halows sal drynk God; for thu ert fadyr that sal restore till me, that es, til my men, myn herytage, that thai lost in Adam: that es thu restores til tham the knawyng of my bryghthede.
Psalm 16:6 Punes ceciderunt michi in preclaris, etc.
Trans. Strynges fel to me in ful bryght: for qwy, myn herytage is ful bryght til me.
Par - Strynges, that er merkes of my possessioun, in thi bryghtnes, fel als with cutte; als the possessioun of prestes and dekens in the alde law, was God; for qwy myn herytage, that es haly men es bryght til me of that seme layth and aute castyng til some of the werld, til me thai er fairer and bryght.

The (e) lines are fallen unto me in pleasant [places]; yea, I have a goodly heritage.
(e) With which my portion is measured.

The lines are fallen unto me in pleasant places,.... The allusion is to the measuring of land by lines, and appropriating each part to the proper owners; and lines design the land that is measured out by them, and here the church and people of God, the chosen ones who are given to Christ, as his portion and inheritance; and the sense is, that Christ's portion lies among or in pleasant persons; such as were so to him, as he saw them in his Father's purposes and decrees; and as they are clothed in his righteousness, and washed in his blood; and as they are adorned with the graces of his Spirit; and as they will be as a bride adorned for him in the New Jerusalem state, for rather persons than places are here meant: though as the bounds of the saints' habitations are set, and they are known to Christ, so they were pleasant to him, and he took delight and rejoiced in the very spots of ground where he knew they would dwell, Proverbs 8:31; and the word "places" is supplied by Aben Ezra and Kimchi: but the former sense seems best, and agrees with what follows;
yea, I have a goodly heritage: so the Lord's people are called, 1-Peter 5:3; these are Christ's heritage, his peculiar treasure, his jewels, with whom he is greatly delighted and well pleased; more than men are with their gold and silver, houses and land, and their greatest wealth and substance: these persons are the inheritance with which he is contented and fully satisfied.

The measuring lines (הבלים) are cast (Micah 2:5) and fall to any one just where and as far as his property is assigned to him; so that נפל חבל (Joshua 17:5) is also said of the falling to any one of his allotted portion of land. נעמים (according to the Masora defective as also in Psalm 16:11 נעמות) is a pluralet., the plural that is used to denote a unity in the circumstances, and a similarity in the relations of time and space, Ges. ֗108, 2, a; and it signifies both pleasant circumstances, Job 36:11, and, as here, a pleasant locality, Lat. amaena (to which נעמות in Psalm 16:11, more strictly corresponds). The lines have fallen to him in a charming district, viz., in the pleasurable fellowship of God, this most blessed domain of love has become his paradisaic possession. With אף he rises from the fact to the perfect contentment which it secures to him: such a heritage seems to him to be fair, he finds a source of inward pleasure and satisfaction in it. נחלת - according to Ew. 173, d, lengthened from the construct form נהלת (like נגינת Psalm 61:1); according to Hupfeld, springing from נחלתי (by the same apocope that is so common in Syriac, perhaps like אמרתּ Psalm 16:1 from אמרתּי) just like זמרת Exodus 15:2 - is rather, since in the former view there is no law for the change of vowel and such an application of the form as we find in Ps 60:13 (Psalm 108:13) is opposed to the latter, a stunted form of נחלתה: the heritage = such a heritage pleases me, lit., seems fair to me (שׁפר, cognate root ספר, צפר, cognate in meaning בשׂר, Arab. bs̆r, to rub, polish, make shining, intr. שׁפר to be shining, beautiful). עלי of beauty known and felt by him (cf. Esther 3:9 with 1-Samuel 25:36 טוב עליו, and the later way of expressing it Daniel. 3:32). But since the giver and the gift are one and the same, the joy he has in the inheritance becomes of itself a constant thanksgiving to and blessing of the Giver, that He (אשׁר quippe qui) has counselled him (Psalm 73:24) to choose the one thing needful, the good part. Even in the night-seasons his heart keeps watch, even then his reins admonish him (יסּר, here of moral incitement, as in Isaiah 8:11, to warn). The reins are conceived of as the seat of the blessed feeling that Jahve is his possession (vid., Psychol. S. 268; tr. p. 316). He is impelled from within to offer hearth-felt thanks to his merciful and faithful God. He has Jahve always before him, Jahve is the point towards which he constantly directs his undiverted gaze; and it is easy for him to have Him thus ever present, for He is מימיני (supply הוּא, as in Psalm 22:29; Psalm 55:20; Psalm 112:4), at my right hand (i.e., where my right hand begins, close beside me), so that he has no need to draw upon his power of imagination. The words בּל־אמּוט, without any conjunction, express the natural effect of this, both in consciousness and in reality: he will not and cannot totter, he will not yield and be overthrown.

Lines - My portion, which was measured with lines. Are fallen - In a land flowing with milk and honey, and above all, blessed with the presence and knowledge of God.