Tafsir of Al-Hijr 15:12

"Thus do We cause it to enter into..."

It is said: "I threaded (salaktu) the needle," and "I caused it to enter (aslaktu-hu)," meaning you inserted it and arranged it.

It is also recited: "We cause it to enter (nasluku-hu)." The pronoun refers to the Reminder (al-dhikr). That is: just as that threading occurs, so do We cause the Reminder to enter into the "hearts of the criminals." This means We cast it into their hearts as something denied and mocked, not accepted.

It is like when you bring a need to a base person and they do not fulfill it for you, so you say: "Thus do I bring it to the base," meaning: "Just as I brought this need to this person and it was rejected and unfulfilled, I bring it to others like them."

The position of the phrase "they do not believe in it" is in the accusative state as a circumstantial qualifier (hal), meaning: "they are not believing in it." Alternatively, it is an explanation of the phrase "Thus do We cause it to enter."

"Say to those..."

This refers to the path that God established in destroying them when they denied their messengers and the Reminder sent down upon them. This is a threat to the people of Mecca regarding their denial.

"And even if We opened for them a gate from the heaven, and they continued to ascend through it, they would surely say: 'Our eyes have only been dazzled; rather, we are a people bewitched.'"