Jami` at-Tirmidhi 3451

Bilal bin Yahya bin Talhah bin `Ubaidullah narrated :from his father, from his grandfather Talhah bin `Ubaidullah that when the Prophet (ﷺ) would see a crescent moon, he would say: “O Allah, bring it over us with blessing and faith, and security and Islam. My Lord and your Lord is Allah (Allāhumma ahlilhu `alainā bil-yumni wal-Īmān, was-salāmati wal-Islām, rabbī wa rabbuk Allāh).”