Sayyiduna Ali ibn Abi Talib raziAllahuanhu said concerning his spiritual companionship with the Prophet Muhammad ﷺ,:
"I was still a young child and the Prophet ﷺ took me into his custody. I used to cling to him and he used to feed me, and (when I grew a little older), he never found me uttering a lie, nor did I ever try to deceive people.
In my eyes he (the Prophet) was like a guiding star and I used to follow his actions and deeds carefully.
I was attached to him like a foal of camel attached to its mother. He used to place before me high values of morality, and used to advise me to follow them; every year, he would spend some days at the grotto of the Mt. Hira and I used to be with him, I was his only companion then and none else could meet him at Hira.
It was there I used to see the light of revelation and used to smell the fragrance of Prophet-hood. Once the Prophet ﷺ told me: "Ali! You have attained a very eminent place. You see what I see and you hear what I hear."
(Recorded in the Tafsir ad-Durr Al-Manthur by Imam Jalaludin Al-Suyuti [ra])
Source: received