Hazrate Khadija (R.A)
All the Aimmah (Imams) of Islam have consensus that Hazrate Khadija (R.A) was the first person who embraced Islam. All the Muslims have Ijmaa (collective understanding) on it that neither a man nor women embraced Islam before Hazrate Khadija (R.A). (Al-Kamal ibn-e-Athir, Vol.II, p.37)
Allamah Ibn-e-Hisham in his Syrat writes:
"Hazrate Khadija bint Khwaylid believed in Holy Prophet (S.A.W), she encouraged the Beloved Prophet (S.A.W) to carry out His Prophetic responsibilities. She was the first in believing in Allah (S.W.T) and His Apostle (S.A.W) and gave evidence of the Prophethood of his Illustrious Majesty.
Whenever Holy Prophet's (S.A.W) opposition spoke bitterly with Him or falsify and tried to disprove Him, it disheartened the Prophet (S.A.W) very much, but whenever He (S.A.W) reached home, Hazrate Khadija (R.A) always softly spoke to Him so that his worries always washed away.
She (R.A) always encouraged and motivated the Beloved Prophet (S.A.W). When the opposition afflicted pain and miseries, Hazrat Khadija (R.A) affirmed Him (S.A.W) and always stood by Him (S.A.W). May Allah (S.W.T) cover her with His eternal blessings. (Al-Syrat-ul-Nabwia, Vol. I, p.259 Ibn-e-Hisham)
Hazrate Khadija (R.A) took lead in believing in Rasoolullah (S.A.W), she solaced and encouraged Him at every step. Due to her love and services to the Beloved Prophet (S.A.W), Allah (S.W.T) sent the Angel Hazrat Jibraeel (A.S) to the Prophet (S.A.W) when he was in the cave of Hira with the Message:
“Ya Rasoolullah (S.A.W)! Pay Salaam of Almighty Allah and mine to Khadija and give her glad tiding that, Allah keeps a special house made of pearls for her in which will be no noise or tedium.”
Hazrate Khadija (R.A) in response said, “Allah Himself is Salaam, and all the Salaams are from Him. Salaam on Jibraeel as well and Ya Rasoolullah! Salaam on you and as well the graces and blessings of Allah (S.W.T).” (Al-Syrat-ul-Nabwiah, Vol.I p.175, Ahmed bin ZainyDahlaan)
In her response, Hazrate Khadija (R.A) , very carefully bore in mind, the etiquettes and the manners worthy of Him (S.A.W), she was sending her Salam too. Her message manifests the faith and the belief of the exalted lady as well as her absolute wisdom and intellect.