All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The angel Jibreel asked the Prophet to repeat after him. He did not bring something written. His saying, “Read,” which meant, “read what I will recite to you”. The Prophet replied: “I am not going to read," which meant: “I refuse to abide by your order to repeat what you are saying.” This is why Jibreel embraced the Prophet thrice. Thereupon, the Prophet accepted to repeat after him.
One might wonder, why did Prophet Muhammad refuse to abide by the orders of the angel? The answer is that until that time, the Prophet was still not sure of the identity of the angel, nor was he aware that Jibreel was sent to him by Allaah The Almighty. The evidence of this is in the rest of this Hadeeth (narration) and the story of Khadeejah and Waraqah ibn Nawfal.
So, what this Christian said is baseless.
Allaah Knows best.