Imam Ibn Jazri (rah) said: When a kafir (i.e.Abu Lahab) against whom a whole Surah has been revealed in Quran, he gets relaxation in hell fire due to night of Prophet (salallaho alaihi wasalam)'s birth, then imagine the status of an Ummati who gets happy on his birth and spends due to his love for him, Allah would indeed give him Jaza and make him enter in His magnificent Paradise.
Ref: Sharh al-Zarqani, volume 1, page 261.
Look how Imam Zarqani (rah) remembers Imam Ibn Jazri (rah) below in Sharh, he says: Al Hafidh Abul Khayr Shams ud din (Ibn Jazri) Muhammad bin Muhammad bin Muhammad al-Dimishqi. "THE IMAM OF RECITATION, THE MEMORIZER OF HADITH, THE AUTHOR OF MANY (VALUABLE) BOOKS.
There is a question being asked about commemorating Mawlid of Prophet in the month of Rabi ul-Awal: What is the religious legal ruling in this regard, is it good or bad? Does the one who celebrates it gets rewarded or not?" ...Answer: The reality of Mawlid is that people gather to recite Quran to the extent that is easy, also to discuss narrations which are regarding Prophet (salallaho alaihi wasalam), the signs which took place on his birth. Then dinning is arranged for them and they return without adding anything more to this "Bidat al Hasanah". The one who arranges it gets Thawab due to honoring Prophet (salallaho alaihi wasalam) and showing gratitude on his birth.
Ref: As-Suyuti – Rahimuhullah in Al Hawi lil Fatawi, volume 1, page 292, Published by Maktaba al Asriya, Beirut, Lebanon.