The D pair on the front side is a single verse, while the D pair on the back side forms its own chiastic structure:
1d) Psa 18:19, He also brought me out into a broad place; He delivered me because He delighted in me;
2d) Psa 18:32-39a, He established my feet on the high places + armed me with strength so that I prevailed:
–> 1a) Psa 18:32, It is God who arms me with strength, and makes my way perfect;
–> 1b) Psa 18:33-34, He establishes my feet on the high places + teaches my hands to make war:
—-> 1) Psa 18:33, He makes my feet like the feet of deer, and sets me on my high places;
—-> 2) Psa 18:34, He teaches my hands to make war, so that my arms can bend a bow of bronze;
–> central axis) Psa 18:35, You have also given me the shield of Your salvation; Your right hand has held me up, Your gentleness has made me great;
–> 2b) Psa 18:36-38, You enlarged my path so my feet did not slip + I have prevailed over my enemies:
—-> 1) Psa 18:36, You enlarged my path under me, so my feet did not slip;
—-> 2) Psa 18:37-38, I have pursued my enemies + overtaken them; they have fallen under my feet;
–> 2a) Psa 18:39a, For You have armed me with strength for the battle.
On the front side, it is God who delivers David from his enemies because God delighted in David. On the back side, God equips David with strength, and teaches his hands to make war, so that when he engages his enemies himself, he prevails over them. In both cases, God is responsible for the deliverance.
But the D pair throws a spotlight on a valid point: sometimes God does for us Himself, and sometimes He gives us what we need, so that we can do for ourselves, as a good Father. If you have ever been disappointed that God has not answered a prayer, consider that the way He answers it might change over time. One time He might answer our prayer by a miraculous healing; another time He might answer the same prayer by refraining from a miraculous healing, and instead teaching how good nutrition or healthy eating and exercising habits enable the body to heal itself. Has He answered both prayers? Yes, but like David, we might carry some responsibility to learn what it is the Lord is teaching, and put it into practice. He does this to grow us up, to increase us in wisdom and understanding, so that perhaps by making the way we walk perfect (complete or whole), we have less need for divine intervention in the future. This is what parents do for their children, because they love them. ♥
There is still so much amazing truth packed into this one psalm, but I think tomorrow, Lord willing, we will go on to Psa 19.