On sighting the new moon, the Prophet (may Allah's peace and blessings be upon him) would say: O Allah, let this new moon appear on us with security and faith

Talhah Ibn ‘Ubaydulllāh (may Allah be pleased with him) reported that whenever the Prophet (may Allah's peace and blessings be upon him) saw the crescent moon on the first, second, or third night of the lunar month, he would say this noble supplication that contains a request to Allah, the Exalted, to let the new moon be accompanied with security against all religious and worldly fears, with persistent and stable faith, and avoidance from deviation. It also contains a request to Allah, the Almighty, to provide safety and Islam. The mentioning of security and safety draws attention to the importance of removing any harm, while mentioning faith and Islam draws attention to the importance of bringing benefits. The Prophet (may Allah's peace and blessings be upon him) ends the supplication saying to the moon that the Lord of them both, the Prophet and the moon, is Allah, the Exalted. This draws attention to the fact that Allah, the Almighty, is far exalted beyond having associates in managing the affairs of His creation. Finally, the Prophet (may Allah's peace and blessings be upon him) supplicates to Allah, the Almighty, to make this crescent moon a carrier of guidance and good.