What does Psalm 18:29 mean?

David depended upon the Lord for victory over the enemy and for strength to accomplish amazing feats. He trusted in the Lord to enable him to scatter the enemy and to scale walls. In the ancient world, cities were protected by walls which were difficult to climb, and there were not yet cannons to knock them down. A large part of military strategy was overcoming the defense provided by walls. So, in this verse, David credits God with giving him military skill and success.

In our own strength we cannot be victorious over the Devil or difficult circumstances, but we can be victorious by trusting the Lord for success. When the Lord commissioned Joshua to lead the Israelites into Canaan and rout its strong inhabitants, He told Joshua not to fear but to obey Him and His Word. He promised: "Do not be frightened, and do not be dismayed, for the LORD your God is with you wherever you go" (Joshua 1:9). Jesus declared, "Apart from me you can do nothing" (John 15:5). However, if we abide in Christ and His words abide in us, we can ask whatever we wish, and the Lord will grant our request (John 15:7).

Reliance on the Lord makes us victorious just as it made David victorious.