God hath spoken in his holiness; I will rejoice… Give us help from trouble: for vain is the help of man. – Psalm 108:7,12

Notice that David, at the time he wrote this Psalm, had discovered the vanity of human confidence. He says, in the 12th verse, “Give us help from trouble: for vain is the help of man.” “My best friend has proved to be a traitor; he that ate bread with me, hath lifted up his heel against me. Those, who said that they would never leave me, and who never did leave me while there was anything to be got out of me, are all gone. I said in my haste, ‘All men are liars,’ but ‘God hath spoken in His holiness; I will rejoice.'” It is grand faith that can rejoice in God when friends go as the swallows fly away in the autumn or drop off as the leaves fade when the summer comes to an end. That was the kind of faith that Habakkuk had when he sang, “Although the fig tree shall not blossom, neither shall fruit be in the vines; the labor of the olive shall fail, and the fields shall yield no meat; the flock shall be cut off from the fold, and there shall be no herd in the stalls: yet I will rejoice in the Lord, I will joy in the God of my salvation.” This is a good crutch for Mr. Ready-to-halt; nay, better than that, surely this will take Ready-to-halt’s crutches away and enable him to run without weariness in the ways of the Lord. Why, brethren. Here are the wings of eagles for you, if you only know how to use them: “God hath spoken.” What a mighty power your soul will have in prayer if you go to God, and say, “Do as Thou hast said.” What a sword this is to flash in the face of the foe: “God hath spoken.” “It is written” is that which makes old Rome to tremble, and her seven hills to quake for fear. Get you a rejoicing grip of this great truth and the dwarf shall become a giant, the feeblest among us shall be as David, and the house of David shall be like the angel of the Lord. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2864.cfm