Jacquees isn't letting Lecrae's comments slide quietly ... the R&B singer is firing back after the gospel star suggested he wasn't good enough for Deiondra Sanders.

We caught up with Jacquees while he was promoting his new single and upcoming album, "Mood 2" ... and you gotta watch the clip, because he wastes no time unloading on Lecrae after hearing the comments for the first time.

The drama stems from a recent podcast appearance featuring Deiondra -- the daughter of NFL legend Deion Sanders -- and Lecrae. During their conversation, Deiondra opened up about her relationship with Jacquees, while Lecrae admitted he was disappointed by the pairing ... telling her, "From the outside looking in ... I wanted more for you."

Jacquees clearly wasn't impressed. In our interview, he argues it's weak for one man to speak negatively about another man he doesn't even know ... adding that guys shouldn't have to tear down someone else to get a woman's attention.

He also takes issue with the fact the criticism came from a gospel artist ... saying he'd expect a different approach from someone in that position. Still, Jacquees ends things on a relatively cordial note, wishing Lecrae well and saying, "God bless him" ... even while making it known he'd rather not hear his name brought up again.

Safe to say ... Lecrae's comments didn't exactly get an "amen" from Jacquees.