Matthew 4:10
Then Jesus said to him, "Away, Satan! for it is written, 'You shall worship the Lord your God and him only shall you serve.'"
Luke 4:8
And Jesus answered him, "It is written, 'You shall worship the Lord your God, and him only shall you serve.'"
Matthew 6:24
No one can serve two masters; for either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve God and mammon.
Matthew 15:8
'These people honor me with their lips, but their heart is far from me.
John 4:24
God is spirit, and those who worship him must worship in spirit and truth."