David merged two images in verse 1—the law court (“plead my cause”; see 43:1; 74:22; Jer. 2:9; Mic. 6:1) and the battlefield. Saul chose the battlefield, but David turned to the Lord and asked Him to be Advocate and Judge in the dispute. “The Lord is a man of war” (24:8; 45:3–5; Ex. 15:3; Josh. 5:13–15), so if Saul wanted a fight, God would accept the challenge (see 18:25–27). A soldier himself, David envisioned the Lord dressed in armor and wielding His weapons. The buckler was a large shield that covered most of the body. The enemy hated David (v. 19), lied about him (v. 11), persecuted him (v. 2), and wanted to hurt him and kill him (vv. 4, 26), so the conflict was a matter of life and death; but there was no just cause for this opposition. (See vv. 7, 19; 38:19; 69:4; 109:3; 119:78, 86, 161.)
David asked the Lord to block the way and stand between him and Saul and his army (v. 3), just as He had done at the exodus (Ex. 14:19ff.). Then he asked that the angel of the Lord (34:7) confuse the enemy, turn them around, and chase them (v. 4). This would lead to their disgrace, defeat, and eventual destruction (v. 8). In verse 26, he repeated the prayer of verse 4. David frequently mentioned that he was a man with a price on his head (37:32; 38:12; 40:14; 54:3; 63:9; 70:2), so it’s no wonder he asked the Lord for a special word of assurance (v. 3; 27:1–3). Confronted by God’s heavenly army, Saul and his men were like the chaff: weightless, worthless, defenseless, and harmless. (See 1:4; 83:13; Isa. 17:13; 29:5; Dan. 2:35; Matt. 3:12). They would try to run on the slippery mountain trails and in the darkness fall to their death or fall into one of their own traps (vv. 7–8). These traps were probably pits with nets over them, covered with branches and leaves. Saul treated David like an animal, but it was Saul and his army who were the animals (vv. 15, 17, 25).
In this psalm, David followed each of his three requests with a song of praise to the Lord (vv. 9–10, 17–18, 27–28), showing that his great desire was to magnify Him. David’s joy was in God’s salvation, for which only God could receive the glory. His whole being (“all my bones”; see 51:8) would give thanks and praise to the Lord. “Who is like unto thee?” (v. 10) reminds us of Israel’s triumph song after the exodus (Ex. 15:11). David knew that God had chosen him to be king of Israel and that his greatest task would be to unite and strengthen the kingdom and lead the people back to God. Israel had an important work to do in the world and David’s leadership was essential.