‘And I think it right, as long as I am in this tent, to stir you up by putting you in remembrance, knowing that the putting off of my tent comes swiftly, even as our Lord Jesus Christ signified to me.'
Indeed as long as he is in his earthly tent he considers it right to continually stir them up, by reminding them of these things, and especially so because he is aware that he must shortly put off this tent, as the Lord Jesus Christ had told him.
The reference to his living in a tent is a reminder of his emphasis in 1 Peter that we are but sojourners here (1 Peter 1:1) and are strangers and pilgrims in the world (1 Peter 2:11), journeying on to our living hope (1 Peter 1:3) and inheritance (1 Peter 1:4). It is a reminder of the brevity of life.
How the Lord had indicated to him that he would shortly die he does not say. He would undoubtedly remember how the Lord had told him that one day others would take him and stretch forth his hands and carry him to where he would prefer not to go (John 21:18), but that was something that he had known ever since the resurrection of Christ. It hardly explains this sense of urgency. This would seem to indicate a clearer and more urgent warning recently received.
Perhaps he had received news of the arrest party coming to take him. Or perhaps it had come in a dream or vision. Or perhaps it was simply the result of an impression made on his heart as he prayed. But whichever way it was he knew that his time was short. He had run his race and the time was drawing near (see 2 Timothy 4:7-8). And the very thought of it takes his mind back to the glory of the Lord Jesus Christ that he, with James and John, had seen when he was on the mount (2 Peter 1:16-18), a mount which he could only call ‘that holy mount' (2 Peter 1:18) because of the awesomeness of their experience. Soon he would see that glory again and be a partaker of that glory to its fullest extent (1 Peter 5:1). That this is his train of thought comes out in his reference to his ‘exodus' in the following verse which had been used of Jesus' death at the Transfiguration.