“Then|| shall my foes turn back, in the day I cry, ||This|| I know, for God is mine! ”
https://ref.ly/Ps56.9;emphbbl

I love this translation in The Emphasized Bible. David wrote it when the Philistines seized him in Gath. The Philistines were an existential threat, not just to David, but to all Israel, so when he says they were his foes, he is not just speaking metaphorically.The difference between David and the Philistines, was that David had God on his side, and God was (and always is) enough. Whatever the Philistines did, was of no concern to David because he knew all that he needed to know: “This I know, that God is mine!”

We would do well to absorb deeply this truth because God has not changed and he watches over his people today, just as he watched over David. Which is incomprehensible if it wasn’t so plainly taught in the Scriptures, the God who spoke the world into existence is for me, the (pathetic, failing, wandering) individual.

As usual, Mr. Spurgeon captures this truth very well:

This I know. This is one of the believer’s certainties, his axioms, his infallible, indisputable verities. For God is for me. This, we know, and we know, therefore, that none can be against us who are worth a moment’s fear.