'Ought' in the Bible

Therefore we ought to give the more earnest heed to the things which we have heard, lest at any time we should let them slip.

And by reason hereof he ought, as for the people, so also for himself, to offer for sins.

For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat.