Isa 1:10 Hear the word of the LORD, ye rulers of Sodom; give ear unto the law of our God, ye people of Gomorrah.
God compares them to Sodom and Gomorrah; listen to God and His law. God is real, not imaginary, not of their making or just a tradition. God lives.
Isa 1:11 To what purpose is the multitude of your sacrifices unto me? saith the LORD: I am full of the burnt offerings of rams, and the fat of fed beasts; and I delight not in the blood of bullocks, or of lambs, or of he goats.
1 Sam 15:22 And Samuel said, Hath the LORD as great delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey is better than sacrifice, and to hearken than the fat of rams.
1 Sam 15:23 For rebellion is as the sin of witchcraft, and stubbornness is as iniquity and idolatry...
Isa 1:12 When ye come to appear before me, who hath required this at your hand, to tread my courts?
Isa 1:13 Bring no more vain oblations; incense is an abomination unto me; the new moons and sabbaths, the calling of assemblies, I cannot away with; it is iniquity, even the solemn meeting.
Isa 1:14 Your new moons and your appointed feasts my soul hateth: they are a trouble unto me; I am weary to bear them.
Isa 1:15 And when ye spread forth your hands, I will hide mine eyes from you: yea, when ye make many prayers, I will not hear: your hands are full of blood.
Why? Because it was not in truth. They were going through empty rituals and they were not even thinking as they did it. It had become a habit with them and they had blood on their hands. They were guilty of sin, murder, rebellion and they had no concern for their condition.
We must be careful to not make church just empty rituals; with or without God in our presence.
John 4:23 But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him.
John 4:24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
We are to offer sacrifices of praise to the LORD from clean hands and clean hearts. We are not to be the dead doing dead rituals to please the spiritually dead. Nor should a place of worship become as a public meeting hall, with no order or reverence towards God.