Musnad Ahmed: Hadith 3020

Abu Jahl came to the Prophet (ﷺ) when he was praying and told him off. The Prophet (ﷺ) threatened him, and he said: Are you threatening me? By Allah I have more supporters than anyone in this valley. Then Allah revealed the words: "Have you (O Muhammad (ﷺ) seen him (i.e. Abu Jahl) who prevents. A slave (Muhammad (ﷺ)) when he prays? Tell me if he (Muhammad (ﷺ)) is on the guidance (of Allah) Or enjoins piety? Tell me if he (Abu Jahl) denies (the truth, i.e. this Qur'an) and turns away?" [al'Alaq 96:9-13]. Ibn 'Abbas said: By the One in Whose hand is my soul, if he had called his supporters, the angels of divine justice would have seized him.