The actor paid tribute to his late friend - who he starred opposite in the 1992 movie 'The Bodyguard' - as he addressed the congregation at the New Hope Baptist Church in Newark, New Jersey, and urged her to go to meet her "heavenly father" with no fear.
He said: "I was your pretend bodyguard once, not so long ago, and now you're gone too soon leaving us with memories. Memories of a little girl who stepped bravely in front of this church, in front of the ones that loved you first, in front of the ones who loved you best, and loved you the longest. And boldly you stepped into the white hot light of the world's stage and what you did is the rarest of achievements you set the bar so high that professional singers, your own colleagues they don't want to sing that little country song, what would be the point now? The only ones who sing your songs are young girls like you who are dreaming of being you some day, and so to you Bobbi Kristina and to all those young girls who are dreaming that dream are maybe thinking they aren't good enough I think Whitney would tell you guard you bodies and guard the precious miracle of your own life and then sing your hearts out knowing that there's a lady in heaven making God wonder how he created something so perfect."
Holding back tears, he added: "So off you go Whitney, off you go, escorted by an army of angels to your heavenly father and when you sing before him don't you worry, you'll be good enough."
As he finished his eulogy, the congregation - which included Whitney's mother Cissy and her 18-year-old daughter Bobbi Kristina - and the choir behind him burst into applause.
Mourners included a host of star names such as Mariah Carey, Forest Whitaker, Oprah Winfrey, Queen Latifah and her long-time producer Clive Davis.
Earlier in his tribute, the 57-year-old Hollywood star recalled how he personally requested Whitney to star opposite him in 'The Bodyguard' and had to convince Warner Bros. to cast an African-American woman opposite him.
He said: "At the height of her fame I asked her to be my co-star in a movie called 'The Bodyguard', I thought she was the perfect choice but the red flags came out immediately, 'Maybe I should think this over a bit.' I was reminded that this would be her first acting role. 'We could also think about another singer,' was the suggestion. "Maybe somebody white, nobody ever said it out loud but it was a fair question. There would be a lot riding on this, maybe a more experienced actress was the way to go, it was clear I really had to think about this. I told everyone that I had taken notice that Whitney was black, the only problem was I thought she was perfect for what we were trying to do. There was a bit of relief in the room when we found out that Whitney was going to be on tour and she wasn't going to be available for our movie. The anxiety came right back when I said we should postpone and wait a year. That was a lot for the studio to accept and to their credit they did but not without a screen test. Whitney would have to earn it. That was the first time I saw the doubt creep into her that she would not be handed the part she would have to be great ... The day of the test came and I went into her trailer after the hair and make-up people were done. Whitney was scared, arguable the biggest pop star in the world wasn't sure she was good enough, she didn't think she looked right, there were a thousand things to her that seemed wrong, I held her hand told her she looked beautiful and that I would be with her every step of the way. That everyone there wanted her to succeed, but I could still feel the doubt."
After recalling how they had to stop the screen test because she'd gone away by herself and put on heavier make-up which ran all down her face due to the hot lights shining on her, he continued: "It's a tree we could all hang from. The unexplainable burden that comes with fame, call it doubt, call it fear, I've had mine and I know the famous in the room have had theirs. I asked her to trust me and she said she would and half hour later she went back into to do her screen test and the studio fell in love with her. The Whitney I knew despite her fame and worldwide success, still asked, 'Am I still good enough, am I still pretty enough, will they like me,' it was the burden that made her great and the part that caused her to stumble in the end. Whitney if you could hear me now I would tell you, you weren't just good enough, you were great you sang the whole damn song without a band, you made the picture what it was, a lot of leading men could have played my part, a lot of guys could have filled that role, but Whitney I truly believe that you are the only one who could have paid Rachel Marron at that time. You weren't just pretty, you were as beautiful as a woman could be and people didn't just like you Whitney they loved you."
The service was held by Pastor Joe Carter and eulogies were also made by Davis, Stevie Wonder and her cousin Dionne Warwick.
Whitney was found dead in the bathtub of her room at the Beverly Hilton hotel on Saturday February 11. She was aged 48.