'Prepare' in the Bible

And Samuel speaketh unto all the house of Israel, saying, 'If with all your heart ye are turning back unto Jehovah -- turn aside the gods of the stranger from your midst, and Ashtaroth; and prepare your heart unto Jehovah, and serve Him only, and He doth deliver you out of the hand of the Philistines.'

go, I pray you, prepare yet, and know and see his place where his foot is; who hath seen him there? for one hath said unto me, He is very subtile.