"It has long been recognized that 2 Samuel 22 is not only one of the oldest major poems in the OT but also that, because Psalm 18 parallels it almost verbatim, it is a key passage for the theory and practice of OT textual criticism."304
This psalm records David's own expression of the theological message the writer of Samuel expounded historically. Yahweh is King, and He blesses those who submit to His authority in many ways. Verse 21 is perhaps the key verse. David learned the truths expressed in this psalm and evidently composed it early in his career (v. 1).
This song shares several key themes with Hannah's song (1 Sam. 2:1-10). Both David and Hannah used horn as a figure of strength at the beginning (v. 3; 1 Sam. 2:1) and rock as a figure for God (v. v. 2; 1 Sam. 2:2). They both referred to divine deliverance (v. 3; 1 Sam. 2:1-2) and ended by equating God's king with His anointed (v. 51; 1 Sam. 2:10). Thus these two songs form a kind of inclusioaround the Books of Samuel and give them unity. Given the similarities each makes its own unique statement as well.305
This is a psalm of declarative praise for what God had done for David. It reflects David's rich spiritual life. While David focused attention on the Lord more than on himself, his emphasis was on the blessings Yahweh had bestowed on him.
We can divide the passage into four sections: the Lord's exaltation (vv. 1-4), the Lord's exploits (vv. 5-20), the Lord's equity (vv. 21-30), and the Lord's excellence (vv. 31-51).306
The reference to God's temple (v. 7) probably means heaven. "Arrows"(v. 15) is a figure for lightning bolts. God had drawn David out of the waters of affliction as Pharaoh's daughter had drawn Moses out of literal dangerous waters (v. 17). God had rewarded David (not saved him) because of his righteous conduct (v. 21). Cleanness (Heb. bor) of hands (v. 21) is a figure describing moral purity that derives from the practice of washing the hands with soda (bor).
"The psalmist is not talking about justification by works, much less about sinless perfection, but about a conscience void of offence [sic] toward God and men' (Acts 24:16)."307
God responds to people according to their conduct (vv. 26-27). He is astute (shrewd) to the perverted (crooked, v. 27) in the sense that He turns them into fools.308The similies in verse 43 picture David's enemies as objects of humiliation and contempt.309
"It is . . . both serendipitous and satisfying that the Song of David, a psalm of impressive scope and exquisite beauty, should begin with The LORD' (v. 2), the Eternal One, and end with forever' (v. 51)."310
