On the authority of Abū Saʿīd—may Allah be pleased with him—in a narration traced back to the Prophet ﷺ: “Shall I not inform you of something I fear for you more than the Antichrist?” They replied, “Indeed, please do.” He said, “It is hidden shirk: a man rises to pray, then beautifies his prayer because he notices another man looking at him.” Recorded by Aḥmad (1).

Akhaaf (more fearful): a superlative form meaning “that which is most to be feared.”

Al-Masīḥ: the bearer of the greatest tribulation. He is called al-Masīḥ either because one of his eyes is wiped out, or because he will traverse the earth swiftly, covering great distances.

Ad-Dajjāl: an intensive form of dajl, meaning “extreme deception” or “great lying.”

Ash-shirk al-khafī (hidden shirk): so called because its perpetrator outwardly presents the act as being for Allah, while inwardly intending someone else.

Yuzayyin ṣalātahu (he beautifies his prayer): he makes it appear finer, lengthens it, and the like.

Overall meaning of the ḥadīth: The Companions were discussing the trial of the Antichrist and were fearful of it. The Prophet ﷺ told them that he feared for them something even more dangerous: associating partners with Allah in one’s intention—something invisible to people. He then defined it as enhancing a deed that should be done for Allah alone merely because people are watching.

Reason for citing this ḥadīth in the chapter: it warns against ostentation and explains exactly what it is.