Matthew 4:10

Then Jesus said to him, "Be gone, Satan! For the Scripture says, 'You must worship the Lord your God, and serve Him alone.'"

Luke 4:8

But Jesus answered him, "The Scripture says, 'You must worship the Lord your God, and serve Him alone.'"

Matthew 6:24

No one can be a slave to two masters, for either he will hate one and love the other, or else he will be devoted to one and despise the other. You cannot be slaves of God and money.

Matthew 15:8

"'This people honor me with their lips, but their hearts are far, far away from me;

John 4:24

God is a spiritual Being, and His worshipers must worship Him in spirit and reality."

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 honor me with their lips, but their hearts are far, far away from me;
John 4:24
God is a spiritual Being, and His worshipers must worship Him in spirit and reality."

Serve him

Matthew 4:10
Then Jesus said to him, "Be gone, Satan! For the Scripture says, 'You must worship the Lord your God, and serve Him alone.'"
Matthew 6:24
No one can be a slave to two masters, for either he will hate one and love the other, or else he will be devoted to one and despise the other. You cannot be slaves of God and money.
Luke 4:8
But Jesus answered him, "The Scripture says, 'You must worship the Lord your God, and serve Him alone.'"