Houston's untimely death at the age of 48 has come as a shock to the music world and those close to her.
Her godmother, soul singer Aretha Franklin, said it was "stunning and unbelievable".
Music mogul Simon Cowell said Houston had "one of the greatest voices I have ever heard in my life, ever".
Civil rights campaigner the Rev Al Sharpton led prayers for the singer during today's Sunday service at the Second Baptist Church, in Los Angeles.
"The morning of the Grammys, the world should pause and pray for the memory of a gifted songbird," he said.
The legendary singer and actress was found unresponsive in her hotel room on Saturday and her death was confirmed later in the day by her publicist.
Houston was the daughter of gospel singer Cissy Houston and grew up singing in church.
She was a close friend of gospel singer CeCe Winans and collaborated with her on a number of tracks, including a cover of "Bridge Over Troubled Water".
After being signed to Arista records in 1983, Houston went on to become one of the most successful female artists of all time, selling 170 million records worldwide and winning six Grammys.
By the nineties she had sealed her place as a diva with a string of hits, including "I Wanna Dance with Somebody", "I Will Always Love You" and "One Moment in Time".
In 1996, she starred in "The Preacher's Wife" and sang the soundtrack, which became the best-selling gospel album of all time.
Her career suffered as her marriage to Bobby Brown hit the rocks and she struggled with substance abuse.
In 2009, she returned with I Look To You, which had strong gospel overtones and hinted at her continuing faith in spite of her battles.
A service was held today in Houston's memory at her former church, New Hope Baptist Church in Newark, New Jersey, where she sang in the choir as a teenager.
Pastor Joe Carter told the congregation: "We thank God for the gift of her unique voice. Others live to be 80 or 90 years old, but when they're gone they leave us with nothing to remember. Whitney left us so many wonderful memories. We remember, we rejoice for that phenomenal one of a kind gift … What I remember best is her singing the praises of Jesus Christ."
Hillsong worship leader Darlene Zschech tweeted: "My heart breaks for Miss Whitney's family today.. Our prayers and love are with you all x Darls."
Wendy Beech-Ward, who is on the Spring Harvest and Youthwork Conference teams, tweeted: Whitney Houston's songs brought happiness to many. It's tragic that her talent and fame seems to [have] given her such pain and sadness."
Christian singer Sarah Walker tweeted: "News of Whitney Houston's death has me feeling heavy."
Gospel rapper Guvna B tweeted one of Houston's best known quotes: "I'm my own devil. I'm either my best friend or my worst enemy".
"Deep quote from her. Pray God comforts her family x," he tweeted.