2 Peter 1:12

Wherefore— That is, "Because in this way alone you can have an admittance into Christ's everlasting kingdom." I will not be negligent, by a common figure signifies, "I will make use of the greatest care and diligence." The present truth was, that the practice of the Christian graces and virtues was necessary to make their calling and election firm. They might indeed have said, "We know these things already." St. Peter, therefore, anticipates such an objection, answering it solidly, and by a beautiful gradation declaring that truths, known and firmly believed, should be often called to remembrance, in order to have their proper influences; and that therefore he would put them in remembrance of these things; that he would do it, not once, but always; and that not only during his life, but likewise after his decease; that is, by leaving those two epistles behind him, as their constant monitors. The teachers of the gospel, after St. Peter's example, should often repeat important truths, though well known and firmly believed; that the people may have them continually in remembrance.