Though still in their twenties, Erica and Tina Atkins, who make up the duo Mary Mary, have had an apprenticeship as songwriters with several cuts on R&B and gospel albums over the past few years, and before that were gospel singers. Thankful is pure gospel music, a series of praise songs and cautionary tales with religious messages, but it is likely to have a broader appeal than most gospel music, as indicated by the success of the lead-off single, "Shackles (Praise You)," prior to the album's release. In part, this is because, writing with producer Warryn Campbell, the sisters have come up with a group of songs that will appeal musically no matter what the listener's religious beliefs, but a second important reason is the vocal quality of the two singers. Just as Columbia act Lauryn Hill expanded the audience for hip-hop with her The Miseducation of Lauryn Hill album in 1998, Mary Mary is likely to push back the barriers for gospel, an event that has been in the making for some years, especially in the work of Kirk Franklin, and that is long overdue. Campbell employs many conventional hip-hop rhythmic ideas and usually is credited with playing "all instruments" on the tracks, but that wouldn't matter if the sisters' melodies and lyrics weren't so effective or their singing so compelling. Even when they take on a traditional tune like the album-closing "Wade in the Water," for which guest producer Andrew Gouché has disingenuously taken the songwriting credit, they reinvigorate the song, turning it into a tour de force of vocalizing. Thankful is a powerful debut by a duo that deserves to be gathering platinum records and Grammy Awards in the near future.