Matthew 4:10

Then said Jesus to him, get thee hence Satan: for it it written, "Thou shalt worship the Lord thy God, and him only shalt thou serve ."

Luke 4:8

but Jesus answered him, avant, satan, for it is written, "thou shalt worship the Lord thy God, and him only shalt thou serve."

Matthew 6:24

no man can serve two masters: for either he will hate the one, and love the other; or he will be attach'd to the one, and neglectful of the other. ye cannot serve God and Mamon.

Matthew 15:8

"this people, says he, draw nigh to me, they honour me with their lips: while their hearts are far from me.

John 4:24

God is a spirit, and they that worship him, must worship him in spirit and in truth.

Treasury of Scripture Knowledge

Summary

And Samuel spake unto all the house of Israel, saying, If ye do return unto the LORD with all your hearts, then put away the strange gods and Ashtaroth from among you, and prepare your hearts unto the LORD, and serve him only: and he will deliver you out of the hand of the Philistines.

Bible References

Prepare

Matthew 15:8
"this people, says he, draw nigh to me, they honour me with their lips: while their hearts are far from me.
John 4:24
God is a spirit, and they that worship him, must worship him in spirit and in truth.

Serve him

Matthew 4:10
Then said Jesus to him, get thee hence Satan: for it it written, "Thou shalt worship the Lord thy God, and him only shalt thou serve ."
Matthew 6:24
no man can serve two masters: for either he will hate the one, and love the other; or he will be attach'd to the one, and neglectful of the other. ye cannot serve God and Mamon.
Luke 4:8
but Jesus answered him, avant, satan, for it is written, "thou shalt worship the Lord thy God, and him only shalt thou serve."