Death mightily moves a sinner to repentance. It is both known to us and unknown. It is known, since we all shall die. It is unknown, since we do not know when and how and where we shall die. The longer we live, the more our life is diminished and our days are shortened and the more we approach death. And we are closer to death today than we were yesterday, this hour than we were the last hour. Death walks invisibly behind every man and seizes him when he least expects it. Almost all people, and especially the healthy and the strong, dream thus within themselves: "I shall live some more, my end is not yet in sight. I shall store up, and indulge myself on my hoarded goods."
But how suddenly death overtakes him, and then all his dreams and plans perish. He who promised himself a long life quickly dies. He who wished to lay up treasures and become rich, leaves both the world and his body in the world. So our end is unknown to us. Christians! God, Who loves mankind, in caring for us has appointed for us our unknown end, that we may always be prepared for it and abide in true repentance.
A man will appear at the Judgement of Christ with what he has when he departs from this world.
Sinners! Let us consider this saying diligently and repent, lest we depart into the next world and appear before that judgement with our sins. Our compassionate God promised to show us His grace and mercy, but He did not promise us the morrow. Let us pay close attention to this and let us awake from sleep, and remembering our death let us correct ourselves and prepare for our departure, that we may have a blessed end. Blessed are the dead which die in the Lord (Apoc. 14:13). He who dies in repentance and faith and true prayer dies in the Lord. That hour is fearful to us all. All the saints looked to that hour and wept, and so they propitiated God Who loves mankind that He should deliver them in that hour. It is a wondrous thing that the saints weep when they look upon that hour, but sinners do not weep though they see their brothers dying every day.
Poor sinners! Why do we sleep? Behold, as a thief the devil steals our salvation. Let us inscribe that hour in our memory and let us be prepared. From that hour on a man will be either eternally blessed or eternally unhappy. Here the door to eternity is opened to each man, and he will go into either a happy or an unhappy eternity. From that point on a man begins either to live eternally or die eternally.
Where now are those who lived before us in luxury and pleasure and remained unrepentant? Departing from this world they abandoned all their comforts, and abiding in their places they await the final judgement, where they will receive perfectly according to their deeds.
Therefore, while that hour has not yet come to us, let us turn to our God with a pure heart and let us be reconciled to Him with repentance that we may obtain eternal life. The holy Apostle exhorts and beseeches us concerning this, We pray you in Christ's stead, be ye reconciled to God. For He hath made Him to be sin for us, Who knew no sin; that we might be made the righteousness of God in Him (II Cor. 5:20-21).
On perpetual repentance and correction of life
Death walks invisibly behind us, and the end will overtake us when we least expect it, and it will overtake us where we least expect, and it will overtake us in a way that we least expect. Abide in perpetual repentance, then, and be prepared for departure at all times and in every place. The wise servant always watches and waits till his master calls him. You, too, should watch and wait till Christ your Lord calls you, for He calls everyone through death. Then always be in your life what you wish to be at death. Always live piously and work out your salvation with fear and trembling (cf. Philip. 2:12). Always and everywhere proceed with caution and guard yourself, lest you be deprived of eternal salvation, which Christ our Lord obtained for us with His Blood and death, and so shall we have a blessed end.
Source: St. Tikhon of Zadonsk, 1991, Journey to Heaven: Counsels on the Particular Duties of Every Christian, Holy Trinity Monastery, New York, pp. 167-169.