Psalm 50's title says it is A Psalm by Asaph. It pictures God holding court over his own people. The Mighty One, God, Yahweh, speaks, and calls the earth from sunrise to sunset. Out of Zion, the perfection of beauty, God shines out. Our God comes, and does not keep silent. He calls heaven and earth as witnesses and says, Gather my saints together to me, those who have made a covenant with me by sacrifice. The heavens shall declare his righteousness, for God himself is judge.
God's first words go to those who worship outwardly. I don't rebuke you for your sacrifices. Your burnt offerings are continually before me. Yet God has no need of their animals. For every animal of the forest is mine, and the livestock on a thousand hills. If I were hungry, I would not tell you, for the world is mine, and all that is in it. Will I eat the meat of bulls? God is not fed by offerings. What he wants is a thankful, trusting heart: Offer to God the sacrifice of thanksgiving. Pay your vows to the Most High. Call on me in the day of trouble. I will deliver you, and you will honor me.
Next God addresses the wicked. They recite his statutes and talk about his covenant, yet they hate instruction and throw his words behind them. They join with thieves, frame deceit, and slander their own brother. Because God was silent, they thought he was just like them. Now he will correct them. The psalm ends with an invitation: Whoever offers the sacrifice of thanksgiving glorifies me, and prepares his way so that I will show God's salvation to him. In the New Testament, Paul writes, In everything give thanks, for this is the will of God in Christ Jesus (1 Thessalonians 5:18).