Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.

 

The hadith is as follows: Abu Hurairah (May Allah be pleased with him) reported:

 

Messenger of Allah (peace be upon him) said, “A strong believer is better and dearer to Allah than a weak one, and both are good. Adhere to that which is beneficial for you. Keep asking Allah for help and do not refrain from it. If you are afflicted in any way, do not say: ‘If I had taken this or that step, it would have resulted into such and such,’ but say only: ‘Allah so determined and did as He willed.’ The word ‘if’ opens the gates of satanic thoughts”.

 

The massive majority of scholar maintained that strength here refers to the firmness in iman and certitude.

 

Almighty Allah knows best.