Commentary on the verse in which Allah, may He be exalted, says (interpretation of the meaning): “And Allah has created you and then He will cause you to die, and of you there are some who are sent back to senility, so that they know nothing...
Question

                I am confused about these two verses

[16:70] Saheeh International

...And among you is he who is reversed to the most decrepit [old] age so that he will not know, after [having had] knowledge, a thing...

[16:70] Hilali & Khan

...and of you there are some who are sent back to senility, so that they know nothing after having known (much)...

[22:5] Hilali & Khan

... and among you there is he who is brought back to the miserable old age, so that he knows nothing after having known....

I want to know does these verses say he knows nothing at all i.e., he forgets each & everything or he forgets only some knowledge because (according to me) a person does not forget everything but he forgets some knowledge.

So I want to know does these verses say:

1)...so that he will not know, after [having had] knowledge, a thing...(which according to me is correct as it says a thing' he used to know so overall it means he forgets some knowledge & not necessarily all) or does it mean:

...so that they know nothing after having known (much)...(which according to me is not correct)

So I want to know what is it's accurate translation & where lies the confusion and moreover does this part(لَا يَعْلَمَ بَعْدَ عِلْمٍ شَيْئًا [16:70 &
لِكَيْلَا يَعْلَمَ مِن بَعْدِ عِلْمٍ شَيْئًا[22:5

mean samething in these two(16:70 & 22:5) verses or does it mean different when read in these two different places.

What are the commentary of scholars on these parts of verses

Does شَيْئًاat the end of verses mean a thing'or 'anything
Praise be to Allah.
	Allah, may He be glorified and exalted, says (interpretation 
	of the meaning): “And 
	Allah has created you and then He will cause you to die, and of you there 
	are some who are sent back to senility, so that they know nothing after 
	having known (much)” [an-Nahl 
	16:70].

	And He, may He be exalted, says (interpretation of the 
	meaning): “And 
	among you there is he who dies (young), and among you there is he who is 
	sent back to senility, so that he knows nothing after having known” 
	[al-Hajj 22:5]. 

	At-Tabari (may Allah have mercy on him) said: 

	Allah, may He be exalted, is saying: Allah created you, O 
	people, and brought you into being, when you had been nothing, and it was 
	not the gods whom you worship besides Him (who created you). Therefore 
	worship the One Who created you, and no other, then He will take your souls 
	in death. 

	And some of you will grow old, and end up reaching a stage of 
	senility, which is the worst 
	of stages. We only bring him back to senility so that he will once again 
	become ignorant, as he was in infancy and childhood, so that he will not 
	know anything after the knowledge that he had when he was young. All of that 
	will be lost when he grows old, and will be forgotten, and he will not know 
	anything of it, for it will escape his mind. So after having possessed the 
	power of rational thinking, he will not understand anything. 

	As-Sa‘di (may Allah have mercy on him) said: 
	

	Here Allah, may He be exalted, tells us that it is He Who 
	creates people and causes them to move through the stages of creation, one 
	after another. Then after their lifespan has ended, He causes them to die, 
	but He causes some to live until they are 
	sent back to senility, 
	i.e., the worst age, in which a person loses his outward and inward 
	strength, even his power of reasoning, which is the essence of man. It grows 
	weaker and weaker, until he forgets what he used to know, and his mind 
	becomes like the mind of an infant. End quote. 

	Tafseer as-Sa‘di 
	(p. 444) 

	Az-Zajjaaj (may Allah have mercy on him) said: 

	What is meant is that among you are some who grow very old, 
	until they lose their power of reasoning, and after having known things they 
	become ignorant. Allah does that in order to show you His might and power; 
	just as He is able to cause a person to die or give him life, He is also 
	able to cause him to move from knowledge to ignorance. End quote. 

	Zaad al-Maseer 
	(2/571) 

	What is meant is that Allah, may He be exalted, causes people 
	to move from ignorance to knowledge, then from knowledge to ignorance, and 
	from weakness to strength, then from strength to weakness. 

	People vary in the extent of this ignorance to which they 
	move. Some of them will become completely senile, so that they do not know 
	anything at all; some of them will hardly know anything; and some of them 
	will know a few things but ignorance and lack of knowledge is mostly the 
	case for them. 

	What is meant by the words of Allah, may He be exalted, “so 
	that he knows nothing after having known” 
	is to highlight the fact that ignorance will prevail after he had knowledge, 
	not to rule out knowledge altogether for everyone who reaches this stage, 
	because saying that he will know nothing is not to be taken literally; 
	rather it is by way of emphasis.   

	Hence Allah says, “and 
	among you”, so as to 
	indicate that not everyone who grows old and reaches old age will be 
	sent back to senility; 
	rather some of them will be 
	sent back to senility so 
	that they do not know anything after having known something, and some of 
	them will grow old but Allah will protect their reasoning, hearing and 
	sight. 

	Ibn Jaziyy (may Allah have mercy on him) said: 

	It does not mean that knowledge is ruled out altogether; 
	rather it is a reference to having little knowledge and to forgetting a 
	great deal. End quote 

	Tafseer Ibn Jaziyy 
	(1/431) 

	Az-Raazi (may Allah have mercy on him) said: 

	If it is asked: How come Allah says: “so 
	that he knows nothing after having known” 
	[al-Hajj 22:5], when he may well know some things, like a child? Our 
	response is: What is meant is that his power of reasoning will be taken 
	away, so he will become as if he does not know anything, because such a 
	thing may be described in the negative for the sake of emphasis. End quote. 

	Tafseer ar-Raazi 
	(23/205) 

	Ibn ‘Ashoor (may Allah have mercy on him) said: 

	Hence there are levels of weakness of reason, depending on 
	the degree of senility. It may go so far as being unable to learn anything 
	new, but before that there are different levels of weakness of reason, such 
	as forgetting things, mixing up information, and so on. End quote. 

	At-Tahreer wa’t-Tanweer 
	(17/202) 

	Conclusion: 

	These two verses do not mean that everyone who grows old will 
	be in this state of “senility”; 
	rather among those who grow old there will be some who are 
	sent back to senility 
	and will be in that state where they forget everything that they knew 
	before. 

	Moreover, this forgetfulness and being 
	sent back to senility are of varying 
	degrees, and people vary in 
	that regard. There are some who forget everything that they knew, and others 
	who suffer to a lesser degree. This is something that is very well known. 

	And Allah knows best.