As for the meaning of disbelief (kufr) in His statement, {Indeed, those who disbelieve}, it is denial (juḥūd). That is because the rabbis among the Jews of Medina denied the prophethood of Muḥammad, peace and blessings of God be upon him, concealed it from the people, and hid his affair, even though they knew him just as they knew their own sons.

The root meaning of kufr among the Arabs is the covering of something. For this reason, they called the night kāfir (coverer), because its darkness covers whatever it clothes, just as the poet said:

So they both remembered a packed heavy burden, after the sun had cast its right hand into a coverer (1)

And Labīd ibn Rabīʿa said:

On a night whose clouds covered the stars (2)

Meaning: covered them. Likewise, the rabbis among the Jews covered the matter of Muḥammad, peace and blessings of God be upon him, and hid it from the people—despite their knowledge of his prophethood and their finding his description in their scriptures—so God, majestic is His praise, said regarding them: {Indeed, those who conceal what We sent down of clear proofs and guidance after We made it clear for the people in the Book - those are the ones cursed by God and cursed by those who curse} [Sūrat al-Baqara: 159]. And they are those regarding whom God, Mighty and Majestic, revealed: {Indeed, those who disbelieve - it is all the same for them whether you warn them or do not warn them, they will not believe}.

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