Chapter 220
Supplication at the Sight of the Crescent (At the outset of Every Lunar Month)

1228. Talhah bin Ubaidullah (May Allah be pleased with him) reported: At the sight of the new moon (of the lunar month), the Prophet (PBUH) used to supplicate: "Allahumma ahillahu `alaina bil-amni wal-iman, was-salamati wal-Islam, Rabbi wa Rabbuk-Allah, Hilalu rushdin wa khairin (O Allah, let this moon appear on us with security and Iman; with safety and Islam. (O moon!) Your Rubb and mine is Allah. May this moon be bringing guidance and good).''
[At-Tirmidhi].

Commentary: After sighting the moon, one should recite the prayer which was recited by the Prophet (PBUH). The prayer cited in the text of this Hadith is one of them.