Summary: David recounts God's faithfulness and protection specifically to kings, of which he is one himself. He says that God not only grants kings long life and prosperity, but defense against their enemies.
Response: Again, I try my best to have respect for the context of David's thoughts. I know that kings were just a thing instead of a distraction as they usually are today. I think I get that, without a long-reigning king, disaster would befall a kingdom. But I have read through I and II Kings, and they're really bad at ruling anyway as well as short lived even when they do obey God. Lord, I pray that, where I lead, help me to serve more and more. Where I follow, help me to respect the position and the one who holds it, and guide my hand to help.