Justin Bieber seems to be claiming he's got nothing to prove to anyone, and he doesn't owe the world anything ... sharing it all in a cryptic social media post.

The singer-songwriter uploaded a text post on a white background to his Instagram story Saturday morning ... and, he seems to be further addressing all the speculation about his health.

He says straight up that nobody has "anything to prove today" and "Nothing is owed to us. And we don't owe anyone anything."

It's not clear exactly what he's referring to here ... but, given all the rumors swirling around him and his family recently, it seems to be addressing the gossip once again.

We broke the story ... Justin and his wife Hailey fired back at all the rumors that he was using drugs again in -- saying through a rep that rumors about Justin using again were absolutely not true.

They also called the persistent narrative about Justin's mental and physical health "exhausting and pitiful and shows that despite the obvious truth, people are committed to keeping negative, salacious, harmful narratives alive."

ICYMI ... photos of Justin appearing tired and a bit disheveled in public threw social media into a frenzy -- though our sources told us he appeared exhausted because he's working on new music and taking care of his newborn son, Jack.

The rumors haven't totally gone away ... and, it looks like JB's pushing back more -- saying he knows the truth and ain't got nothing to prove.