Explanation of the words of Imam al-Nawawi (may Allah have mercy on him) regarding what he quoted: "

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful.
The author said: The author (may Allah have mercy on him) said, in what he quoted from Abu Hurayrah (may Allah be pleased with him) from the Prophet (peace and blessings be upon him), that he said: The strong believer means strong in his faith, and it is not intended to mean strong in his body, because physical strength can be a harm to a person if he uses that strength in disobedience to Allah. Physical strength is neither praiseworthy nor blameworthy; if a person uses that strength in what benefits him in this world and the Hereafter, it becomes praiseworthy, and if he uses that strength to aid in disobedience to Allah, it becomes blameworthy. But the strength in the saying of the Prophet (peace and blessings be upon him) means strong in faith. And because the word “strong” refers back to the previous description, which is faith, just as you say “the strong man” meaning strong in his manliness, so the strong believer means strong in his faith. Because the strong believer in his faith, his strength of faith carries him to perform what Allah has made obligatory upon him, and to increase in voluntary acts as much as he wishes. And the weak believer, his faith is weak and does not carry him to perform the obligatory acts and leave the forbidden ones, so he falls short in many ways.
And his saying means better than the weak believer and more beloved to Allah than the weak believer. Then he (peace and blessings be upon him) said meaning the strong believer and the weak believer, each of them has good in him. And he only said so that no one among people would imagine that there is no good in the weak believer. Rather, the weak believer has good, good that is better than that of the disbeliever, without doubt.