Correction: How glorious is the bitterness of a soul that can still keep singing joyfully to all those who miss solace. Remain cheerful in serving all people.

I think the 1st sentence is missing the verb, singing should be in Present Simple, and soul is missing "the". How glorious is a bitterness of the soul that can still sing joy to those who missed the solace. 2nd I think should be: Keep cheerfulness of serving (to) all people. or Stay cheerful in serving (to) all people.