Al-ʿAllāmah Muḥammad ibn Ṣāliḥ al-ʿUthaymīn notes: The author (Imām al-Nawawī, may Allāh have mercy upon him) titles [his chapter]: The Chapter of Urging Towards Increasing in Good Deeds in the Latter Part of one’s Life.
Know that the latter part of one’s life is crucial, as the Messenger of Allāh (ﷺ) mentioned: Verily one of you performs the actions of the people of Paradise until there is only an arm’s length between him and it, and that which has been written overtakes him, so he acts with the actions of the people of the Hellfire and therefore enters it. And verily one of you performs the actions of the people of the Hellfire, until there is only an arm’s length between him and it, and that which has been written overtakes him, so he acts with the actions of the people of Paradise and therefore enters it.
Likewise, we have from the reported supplications: O’ Allāh, make the latter part of my life the best [part]. And make my last actions the best.
Also, it has been authenticated from the Messenger of Allāh (ﷺ) that he mentioned:
Whoever’s last words in the dunya is that there is no deity worthy of worship in truth except Allāh, will enter paradise.
So that which is required from the person, as he increases in age, is that he also increases in righteous actions. Likewise, the youth should also increase in righteous actions because one does not know when he will die. He may die in his youth or his death may be delayed, but their is no doubt that the one who is older in age is closer to death than the youth because he is at the end of his life.
Source: Sharḥ Riyāḍ al-Ṣāliḥīn li Ibn al-ʿUthaymīn, Chapter #12, Pg. 461, [Dār al-Fajr li-Turāth, Cairo. First Edition, 2005].
Translated by: Munīb al-Ṣumālī