'With All Your Heart' in the Bible

And Samuel spoke to all the house of Israel, saying, If ye return to Jehovah with all your heart, put away the strange gods and the Ashtoreths from among you, and apply your hearts unto Jehovah, and serve him only; and he will deliver you out of the hand of the Philistines.

And Samuel said to the people, Fear not: ye have done all this wickedness; yet turn not aside from following Jehovah, and serve Jehovah with all your heart;

Only, fear Jehovah, and serve him in truth, with all your heart; for see how great things he has done for you.