بِسۡمِ ٱللهِ ٱلرَّحۡمَـٰنِ ٱلرَّحِيمِ

Al-Bukhariyy and others narrated from the route of Ibn ^Abbas (may Allah raise his rank) that the Messenger of Allah (sallallahu ^alayhi wasallam) said: 

رواه البخاري وغيره

Which means: "There are two great endowments which many people are not benefiting from wisely: they are the good health and the free time".

In this hadith the Prophet urged us to use our bodies when we are in a good health and our free time in the right and beneficial way. He also showed us the great loss of the one who doesn’t know how to use these two great endowments in obedience to Allah.

Such a person will regret after he loses these endowments. On Judgement Day, this person will regret having wasted his time at a time when regret is of no use.

On the other hand, the one who has a good health and occupies his free time in obeying Allah will be a happy person in the Hereafter. So let one work in da^wah by learning the religion and teaching it, to succeed in the Akhirah hereafter.