Normally we do not speak of the service that God hates, and it may sound strange to our ears to think that God would hate service that is done in His name. Regardless, we can hear the witness of the prophet in Amos 5:21-23:
I hate, I despise your feasts, and I will take no delight in your solemn assemblies. Yea, though ye offer me your burnt-offerings and meal-offerings, I will not accept them; neither will I regard the peace-offerings of your fat beasts. Take thou away from me the noise of thy songs; for I will not hear the melody of thy viols.
Many would contest what Amos says: after all, God Himself commanded these things in the Law, did He not? Why would God all of a sudden now despise the feasts, the assemblies, and all the offerings that were made to Him? Why is He not happy with this service? The answer is partly revealed in Amos 5:24:
But let justice roll down as waters, and righteousness as a mighty stream.
Amos chastises the people for the same reasons as Isaiah in Isaiah 1:10-18: they go through the motions of the officially prescribed actions of religious service as dictated in the Law, yet their personal lives do not reflect the will of God. They are willing to fulfill the physical rituals of the Law, but do not have the necessary “heart service” leading to justice and righteousness that God likewise demanded in the Law.
While the precise actions may be different in the new covenant, Jesus indicates the same type of sentiment in Matthew 9:12-13:
But when he heard it, he said, “They that are whole have no need of a physician, but they that are sick. But go ye and learn what this meaneth, ‘I desire mercy, and not sacrifice’, for I came not to call the righteous, but sinners.”
Jesus, quoting Hosea 6:6, indicates that the Pharisees are self-deceived and self-condemned for believing that holding to their traditions would suffice for service without having the requisite “heart service” of love, mercy, and faithfulness toward God. It is easy for us to fall into the same trap. Let us always remember in our humility how we are but recovering sinners, and to not neglect love and mercy and peace while engaging in other parts of our service.