Matthew 4:10

Then Jesus saith to him, Get thee hence, Satan; for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.

Luke 4:8

And Jesus answering said to him, Get thee hence, 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 cleave to the one and neglect the other.

Matthew 15:8

This people draweth nigh to me with their mouth, and honoureth me with their lips; but their heart is 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 draweth nigh to me with their mouth, and honoureth me with their lips; but their heart is 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 Jesus saith to him, Get thee hence, 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 cleave to the one and neglect the other.
Luke 4:8
And Jesus answering said to him, Get thee hence, Satan; for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.