I have lots of things that might be what you are looking for.
You mentioned Mahalia Jackson, but if you don't have the Live at Newport recording that's fairly essential. Aretha Franklin "Amazing Grace: The Complete Recordings" is imo the best thing she ever did.
AMG Wrote:
Among Aretha aficionados, Amazing Grace has long been considered one of her high-water marks, since it captured her glorious return to her gospel roots in front of a live audience. The original 1972 album contained just 14 tracks, culled from two live performances with the Southern California Community Choir, Ken Lupper, and the Rev. James Cleveland at the New Temple Missionary Baptist Church in Los Angeles. Fans have long wished for the release of the two complete concerts — which is exactly what Rhino's Amazing Grace: The Complete Recordings gives them. Over the course of two discs and 29 tracks, every performance Franklin gave that January, along with comments from Cleveland and solo tracks from Lupper and the Choir, is unfurled, and if anything, the music is even more impressive when heard complete and unedited. Of course, the nature of this set makes it of interest primarily to dedicated fans, but they'll likely be delighted by the entire package.
I'd also recommend a few comps:



The first two being Soul Jazz's two comps covering the intersection of soul and gospel. The last being "Good God: A Gospel Funk Hymnal" which mines the same vein.
There are obviously a ton of soul artists that have their roots in gospel and tended to move back and forth from secular soul to gospel. Rev. Al Green and Candi Staton come to mind but there are tons of artists this would apply to. I don't think I've heard any of the gospel recordings of either but I doubt that they wouldn't be strong, just based on the quality of their secular work.
I think I have a lot more that might fit but you'd need to clarify what you are looking for.
For example, do either, both or none of the following meet what you are looking for?
The Voices of East Harlem "Right on Be Free"
DustyGroove Wrote:
The rare first album by this legendary 70s soul group -- and one with a feel that's much different than their later work! The style here is much more strongly righteous -- with a pronounced gospel influence that focuses most strongly on the chorus vocals of the ensemble -- soaring out with a tremendously soulful feel, and really updating an older sound for a more contemporary sort of 70s vibe! Backing is relatively stripped-down, with piano by Patti Brown, organ by Ralph Tee, and guitar by Cornell Dupree -- making for an overall sound that's also a bit less polished than the group's records for the Just Sunshine label. Titles include "Oh Yeah", "Let It Be Me", "Right On Be Free", "Simple Song Of Freedom", and a nice version of "For What It's Worth".
They really sound like they took some amazing Harlem Church Choir and gave them secular material to perform. Almost all of it covers including Buffalo Springfield and CCR. I put their cover of "For What It's Worth" on an obner mix and even though its not a particularly religious tune, got comments that it was too churchy from a lot of the reviewers based on the gospel feel to the choir.
Many of Van Morrison's late 80's/early 90's albums have strong spiritual themes to them with many religious themed songs For example, "Avalon Sunset" has the songs "Whenever God Shines His Light on Me" and "When Will I Learn to Live in God") mixed with more secular themed songs.
AMG Wrote:
Van Morrison scored one of his biggest commercial successes with Avalon Sunset, a record highlighted by the gorgeous "Have I Told You Lately," one of his most heartfelt love songs and a major radio hit which helped introduce his music to a new generation of listeners. Not a consistently strong LP, Avalon Sunset is nevertheless the work of a master craftsman, its lush orchestration and atmospheric production casting an irresistibly elegant spell; a deeply spiritual record, it also includes the standout opener, "Whenever God Shines His Light," a collaboration with Cliff Richard.
Spiritual Jazz is my favorite type of jazz so if that's something you're interested in I can give you lots of recommendations but even though its spiritual, most of it isn't really religiously themed.