What does Psalm 18:39 mean?

David's victories (2 Samuel 8:1–8) led him to praise God—however, they didn't make him arrogant or self-centered. The acknowledgement David has offered in this Psalm is that the Lord is the ultimate source of his success (Psalm 18:1–3; 32–36). David remained humble and grateful to the Lord for the success he realized. It was God, not David, who originated the strength needed to obtain victory. Because the Lord equipped him with strength, David saw his foes fall under his feet.

The apostle John pays tribute to the Lord and His Word for the victories his readers realized in their spiritual lives. He addresses the young men as those who "have overcome the evil one" (1 John 2:13). He adds in 1 John 2:14 "I write to you, young men, because you are strong, and the word of God abides in you, and you have overcome the evil one."

When we experience victory over a temptation, we need to be humble and grateful to the Lord for the victory. It is presumptuous and dangerous to think we were victorious in our own strength. First Corinthians 10:12 warns: "Let anyone who thinks that he stands take heed lest he fall." Proverbs 16:18, too, warns, "Pride goes before destruction, and a haughty spirit before a fall." David did not fall at the feet of his enemies because he humbly credited God with his strength.