Truth will bear repetition

^12-15 I shall not fail to remind you of things like this although you know them and are already established in the truth. I consider it my duty, as long as I live in the temporary dwelling of this body, to stimulate you by these reminders. I know that I shall have to leave this body at very short notice, as our Lord Jesus Christ made clear to me. Consequently I shall make the most of every opportunity, so that after I am gone you will remember these things.