It is narrated from a Companion (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: On the morning of Laylat al-Qadr, I looked at the moon and it was like half a bowl. Abu Ishaq says that the moon appears in this shape on the 23rd night.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 23129