Albert Barnes, Source unknown
It was important for Peter to bring known truths to remembrance. Believers are apt to forget them, and then they do not exert the influence that they ought. Amid the cares, the business, the amusements, and the temptations of the world, the ministers of the gospel render us an essential service, even if they do nothing more than remind us of truths which are well understood, and which we have known before. A pastor need not always aim at originality; he renders an essential service to mankind when he reminds them of what they know but are prone to forget. He endeavors to impress plain and familiar truths on the heart and conscience, for these truths are most important for mankind. Though we may be very firm in our belief of the truth, yet it is appropriate that the grounds of our faith should be stated to us frequently, that they may be always in our remembrance.