Charles Spurgeon Commentary Amos 5:20-22

"Shall not the day of Jehovah be darkness, and not light? even very dark, and no brightness in it? 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." — Amos 5:20-22 (ASV)

See how God speaks about public worship and formal sacrifices when the heart is not right with him. When the moral conduct of the offerer is wrong, the Lord will not accept his offering.