Subsequent to going to Waraqah bin Nawfal alone, Hazrat Khadijah (radhiyallahu ‘anha) took Rasulullah (sallallahu ‘alaihi wasallam) with her to see him. She addressed Waraqah saying, “O my cousin! Why don’t you hear what happened to your nephew (in his own words)?”
Waraqah then addressed Rasulullah (sallallahu ‘alaihi wasallam) saying, “O nephew! Tell me, what did you observe?” Rasulullah (sallallahu ‘alaihi wasallam) then narrated the entire incident.
فلما سمع كلامه أيقن بالحق واعترف به
“The moment Waraqah heard what Rasulullah (sallallahu ‘alaihi wasallam) said, he was immediately convinced that it was the truth. He also acknowledged that it was the truth and accepted it.”
After hearing the entire incident, Waraqah remarked, “Indeed, this is the same angel that used to appear before Nabi Moosa (‘alaihis salaam). If only I was strong and powerful during the period of your prophethood when your people will banish you from your birthplace, or if only I was at least alive at that time.” Extremely surprised by what he just said, Rasulullah (sallallahu ‘alaihi wasallam) asked, “Will they really drive me out?” Waraqah replied, “This is not confined to you alone. Whenever a person became the prophet of Allah Ta‘ala and brought His message to the people, they showed him enmity and hostility. If I am fortunate enough to be alive in that era, I will assist you in all earnestness.” However, not long thereafter, Waraqah passed away.
(Extracted from Seeratul Mustafa 1/139-141)