Matthew 4:10
Then Jesus saith to him, "Depart, Satan; for it has been written, 'You shall worship the Lord your God, and Him only shall you serve.'"
Luke 4:8
And Jesus, answering, said to him, "It has been 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 hold to one, and despise the other. Ye cannot serve God and Mammon.
Matthew 15:8
'This people honor Me with their lips, but their heart is far from Me.
John 4:24
God is a spirit; and those who worship Him must worship in spirit and truth."