In the day when I cried to thee, etc. Frequently God prevents our prayers, and surprises us, as it were, sleeping: but commonly he stirs us up to prayer by the influence of his Spirit, and this to illustrate his goodness the more by our finding that he crowns our prayers with success. David well infers that his escape front danger could not have been merely fortuitous, as it plainly appeared that God had answered him. This then is one thing noticeable, that our prayers more nearly discover his goodness to us. Some supply a copulative in the second part of the verse -- Thou hast increased me, and in my soul is strength. But this is not called for, since the words read well enough as they stand, whether we render the passage as I have done above, or translate it, Thou hast multiplied, or increased, me with strength in my soul. The sense, is, That from a weak and afflicted state he had received fresh strength to his spirit Or some may, perhaps, prefer resolving it thus: Thou hast multiplied -- that is, blest me, whence strength in my soul.

In the day when I cried - Referring to some former period of his life when he was in trouble.
Thou answeredst me - In the very day when I called, thou gavest me the answer: that is, immediately.
And strengthenedst me with strength in my soul - literally, "Thou didst embolden - or, didst make me courageous with strength." Thou didst enable me to meet danger, and to overcome fear. It would seem probable that this was on some occasion when he was in danger from his enemies.

With strength in my soul - Thou hast endued my soul with many graces, blessings, and heavenly qualities.

In the day when I cried thou answeredst me, [and] (c) strengthenedst me [with] strength in my soul.
(c) You have strengthened me against my outward and inward enemies.

In the day when I cried thou answeredst me,.... When in distress through Saul's persecution, he cried to the Lord, and he immediately answered him, and delivered him out of his troubles; and such immediate answers of prayer are to be remembered with thankfulness: see Psalm 18:6;
and strengthenedst me with strength in my soul; put him good heart and spirit, when before ready to faint; strengthened his heart and grace in it, particularly faith, and drew it forth into lively act and exercise so that he sunk not under the weight of affliction and trouble, but was filled with courage to withstand his enemies, and with strength to do the will and work of God; this is to be understood of inward spiritual strength; see Ephesians 3:16.

That promise, as an answer to his prayers in distress, revived and strengthened his faith; and, as the basis of other revelations of the Messiah, it will be the occasion of praise by all who hear and receive it (Psalm 68:29, Psalm 68:31; Isaiah 4:3).

There are two things for which the poet gives thanks to God: He has answered him in the days of trouble connected with his persecution by Saul and in all distresses; and by raising him to the throne, and granting him victory upon victory, and promising him the everlasting possession of the throne, He has filled him with a proud courage, so that lofty feeling has taken up its abode in his soul, which was formerly fearful about help. Just as רהב signifies impetuosity, vehemence, and then also a monster, so הרהיב signifies both to break in upon one violently and overpowerlingly (Song 6:5; cf. Syriac arheb, Arabic arhaba, to terrify), and to make any one courageous, bold, and confident of victory. בּנפשׁי עז forms a corollary to the verb that is marked by Mugrash or Dech: so that in my soul there was עז, i.e., power, viz., a consciousness of power (cf. Judges 5:21). The thanksgiving, which he, the king of the promise, offers to God on account of this, will be transmitted to all the kings of the earth when they shall hear (שׁמעוּ in the sense of a fut. exactum) the words of His mouth, i.e., the divine אמרה, and they shall sing of (שׁיר with בּ, like דּבּר בּ in Psalm 87:3, שׂיח בּ in Psalm 105:2 and frequently, הלּל בּ in Psalm 44:9, הזכּיר בּ in Psalm 20:8, and the like) the ways of the God of the history of salvation, they shall sing that great is the glory of Jahve. Psalm 138:6 tells us by what means He has so super-gloriously manifested Himself in His leadings of David. He has shown Himself to be the Exalted One who is His all-embracing rule does not leave the lowly (cf. David's confessions in Psalm 131:1; 2-Samuel 6:22) unnoticed (Psalm 113:6), but on the contrary makes him the especial object of His regard; and on the other hand even from afar (cf. Psalm 139:2) He sees through (ידע as in Psalm 94:11; Jeremiah 29:23) the lofty one who thinks himself unobserved and conducts himself as if he were answerable to no higher being (Psalm 10:4). In correct texts וגבה has Mugrash, and ממרחק Mercha. The form of the fut. Kal יידע is formed after the analogy of the Hiphil forms ייליל in Isaiah 16:7, and frequently, and ייטיב in Job 24:21; probably the word is intended to be all the more emphatic, inasmuch as the first radical, which disappears in ידע, is thus in a certain measure restored.
(Note: The Greek imperfects with the double (syllabic and temporal) augment, as ἑώρων, ἀνέῳγον, are similar. Chajuǵ also regards the first Jod in these forms as the preformative and the second as the radical, whereas Abulwald, Gramm. ch. xxvi. p. 170, explains the first as a prosthesis and the second as the preformative. According to the view of others, e.g., of Kimchi, יידע might be fut. Hiph. weakened from יהדע (יהידיע), which, apart from the unsuitable meaning, assumes a change of consonants that is all the more inadmissible as ידע itself springs from ודע. Nor is it to be supposed that יידע is modified from יידע (Luzzatto, 197), because it is nowhere written יידע.)