What is the ruling on one who returns the greeting in secret?

Question:
Also, this part of the question says: And if he returns the greeting in secret, and the Muslim does not hear it, what is upon him as well?

Answer:
If one returns the greeting in secret and does not raise his voice so that the Muslim hears it, the ruling is that he has not returned it; he has not returned the greeting. The purpose is to return it in a way that the Muslim hears, so that he has returned his greeting with the like of it or better. This may be due to arrogance, and if it is due to arrogance, it becomes even worse.
The point is that he has not returned the greeting if he did not raise his voice. He has not returned the greeting until he raises his voice in a way that the Muslim hears it. Yes.