Tafsir of Al-An'am 6:109

{And they swore by Allah their strongest oaths that if a sign came to them, they would surely believe in it.}

{Say: "The signs are only with Allah."} He is capable of them, but He only sends them down according to the requirements of wisdom. Or, it means: The signs are with Allah, not with me; so how can I respond to your request for them and bring them to you?

{And what makes you perceive} What makes you know?

{that it} That the sign you are requesting.

{if it came, they would not believe in it?} Meaning: I know that if it came, they would not believe in it, while you do not know that. This is because the believers were hopeful for their faith if that sign were to come, and they wished for its arrival. So, the Almighty said: "And what makes you know that they will not believe?"—meaning, you do not know what has preceded in My knowledge regarding their lack of belief. Do you not see His saying: {as they did not believe in it the first time}?

It is said that {أنها} (that it) is in the sense of "perhaps" (la'allaha), based on the Arabs' saying: "Go to the market, perhaps (annaka) you will buy meat." Imru' al-Qays said: Stop at the desolate ruins, perhaps (li-annana) we may weep for the dwellings as Ibn Khudham wept.

This is supported by the reading of Ubayy: "Perhaps (la'allaha) if it comes, they will not believe."

It is also read with the kasra (innaha), implying that the speech was completed before it, meaning: "And what makes you perceive what will come from them?" Then He informed them of His knowledge regarding them, saying: "Indeed, if it comes, they will not believe at all."

Some consider the "la" (not) to be an addition in the reading with the fatha (annaha).

It is also read: {And what makes them perceive that if it comes, they will not believe?}—meaning, they swear they will believe when it arrives. And what makes them perceive that their hearts will not be, at that time, just as they were when the Qur'an and other signs were revealed—sealed over, so they would not believe in it?

{And We will turn their hearts and their eyes just as they did not believe in it the first time, and We will leave them in their transgression, wandering blindly.}