A Subtle Point: How Did Khubab Know That Their Reward Had Been Guaranteed by Allah (Mighty and Majestic)?

The Shaykh : Here is a brief pause: How did Khubab ibn al-Urt know that when they struggled in the path of Allah, seeking the Face of Allah, their reward was guaranteed by Allah? How did he know that? This is a necessary matter in Islam, based on the promise of Allah (Mighty and Majestic) to His believing servants in dozens of texts in the Book, and even more in the Sunnah, that whoever does such and such will receive such and such. The promise of Allah (Mighty and Majestic) is not delayed, . So when the believer knows this reality, he is certain that if he knows he has performed a pure deed for the Face of Allah (Mighty and Majestic), that Allah (Blessed and Exalted is He) must reward him for it; it is a must. And what you heard in the previous lesson from some of the answers by the professor "Ali Khushan," that they used to fear that their deeds would not be accepted, indicates what you heard explained in that session: that the Companions feared Allah (Mighty and Majestic), and they lived between fear and hope. Not because they doubted that if they knew a good deed and were sincere in it for Allah (Mighty and Majestic), that Allah would not accept it from them; no, how is that? How can a doubter doubt a deed that its doer first performed in accordance with the Sunnah, and then was sincere in it for Allah (Mighty and Majestic)? How can one imagine doubting that Allah (Mighty and Majestic) would accept his work, when Allah says in the clear text of the Noble Qur'an: ?
So their doubt was not regarding the acceptance by Allah of their good deed in which they were sincere for Allah, but rather their doubt was about themselves; perhaps their deed was not good; meaning: it was not in accordance with the Book and the Sunnah. This is the first condition, as you all know, for the acceptance by Allah (Mighty and Majestic) of worship: that it be in accordance with the Sunnah. The second condition is that its doer has been sincere for Allah in it. So how can a person be constantly and eternally, in every deed he does, certain that this deed of his was in accordance with the Book and the Sunnah on one hand, and that he was sincere in it for Allah (Mighty and Majestic) on the other hand? From this, they feared that Allah (Mighty and Majestic) would not accept from them. So from what we mentioned, such as the previous verse and what we referred to besides it, Khubab ibn al-Urt was certain that their reward was guaranteed by Allah (Mighty and Majestic); meaning that Allah accepted it from them and that He will reward them for it.