'Serve' in the Bible

Then David said, None ought to carry the ark of God but the Levites, for them has Jehovah chosen to carry the ark of God, and to serve him for ever.

And thou, Solomon my son, know the God of thy father, and serve him with a perfect heart and with a willing mind; for Jehovah searches all hearts, and discerns all the imaginations of the thoughts. If thou seek him, he will be found of thee; but if thou forsake him, he will cut thee off for ever.