Allah SWT sent His beloved Prophet (صلى الله عليه وسلم) with radiance. There is mention of this in His word- The Holy Quran also "Lo! There has come to you a Noor the Prophet and a lucid book"-Surah Maida (5:15)
The Exegetes (Mufassirin) have explained this verse. The “Noor” mentioned here is the Holy Prophet (صلى الله عليه وسلم) and the book is the Holy Quran. Tafseer Jalalyn, Baydhawi, Ma’alim ut Tanzeel, Tafseer Kabir etc. Musnad e Ahmad, Tabarani and Baihaqi have a Hadith on the authority of Hadhrat Abu Umama (May Allah be well pleased with him) that the Holy Prophet (صلى الله عليه وسلم) said, "I am the prayer of my forefather Ibrahim (Peace be upon him) and the greeting of Hadhrat Isa (Peace be upon him). When I was in her womb, my mother saw that a radiance issued forth from her womb and even the mansions of Syria were lighted up with it."- Khasais Kubra, Vol 1, Pg No: 46.
The radiance of His face was such that His mere presence would light up a place. His radiance would eclipse the light of any lamp, even the sun. It would seem that the sun would draw from the face of the Holy Prophet (صلى الله عليه وسلم).
Hadhrat Aisha (May Allah be well pleased with her) narrates, "The Holy Prophet’s (صلى الله عليه وسلم) face was the most beautiful among all men and His Complexion was the most luminous."
Hadhrat Abdullah bin Umar (May Allah be well pleased with him) says, "I have never seen anybody stronger and braver; more generous and more benevolent, more pure and more radiant than the Holy Prophet (صلى الله عليه وسلم)." (Sunan Darmi, Vol 1, Pg No: 30)
Hadhrat Abdullah bin Abbas (May Allah be well pleased with them) says, “The Holy Prophet (صلى الله عليه وسلم) had no shadow. His radiance would eclipse even the bright sun. In front of a lighted lamp, His radiance would be more powerful.” (Subul ul Huda war rashad, Vol 2, Pg No: 39/40)
The luminosity of his face would further increase on occasions of happiness and joy. As Hadhrat Ka’ab bin Malik (May Allah be well pleased with him) says, "Whenever the Holy Prophet (صلى الله عليه وسلم) was happy, His face would become even more luminous." (Sahih Bukhari, Vol 1, Pg No: 502)