Matthew 4:10

Then Jesus said to him: Get behind me, Satan, for it is written: You shall worship the Lord your God, and him only shall you serve.

Luke 4:8

And Jesus answered and said to him: Get behind me, Satan; 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 he will either hate the one and love the other; or he will hold to the one, and neglect the other. You can not serve God and riches.

Matthew 15:8

This people draws near to me with their mouth, and honors me with their lips; but their heart is far from me.

John 4:24

God is 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 draws near to me with their mouth, and honors me with their lips; but their heart is far from me.
John 4:24
God is spirit; and they that worship him, must worship him in spirit and in truth.

Serve him

Matthew 4:10
Then Jesus said to him: Get behind me, Satan, for 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 he will either hate the one and love the other; or he will hold to the one, and neglect the other. You can not serve God and riches.
Luke 4:8
And Jesus answered and said to him: Get behind me, Satan; it is written, You shall worship the Lord your God, and him only shall you serve.