What does Psalm 50:9 mean?

The Lord is judging Israel (Psalm 50:1–6), though they have been consistent in offering their obliged sacrifices (Exodus 29:38–42; Psalm 50:7–8). The issue at hand is not whether they performed those rituals, but whether their hearts were aligned with God, at all. Here, God makes it clear that He will reject those efforts—even though He commanded them, Himself—because Israel is only hypocritically playing along (Psalm 50:16–21). Their sacrifices do not represent humility and dependence (Hosea 6:6).

Isaiah laid a similar charge against the people of Israel. He delivered a stern indictment from the Lord. Isaiah 1:11 quotes the Lord: "What to me is the multitude of your sacrifices? says the Lᴏʀᴅ; I have had enough of burnt offerings of rams and the fat of well-fed beasts; I do not delight in the blood of bulls, or of lambs, or of goats." Clearly, God disdains the practice of ritualistic worship that rises from a cold heart. Jesus said, "God is spirit, and those who worship him must worship in spirit and truth" (John 4:24).