If i had to pick a favourite artist/composer, it would probably be J.S. Bach, specifically his sacred cantatas. The blend of beautiful harmony, a moving, often poetic setting of great passages from biblical texts as well as original poems, the great instrumentation and, of course, the contrapunctal movements. Nearly all of them are absolutely divine, and they never fail to move me, often to tears.
Heres a few i've been enjoying recently.

https://www.youtube.com/watch?v=rWY02RC2LSQ
https://www.youtube.com/watch?v=ln9MBa8lXV4
https://www.youtube.com/watch?v=MQl42VeDqmU