The Messenger of Allah ﷺ said to me: The sign that you have been permitted to come in is that the curtain is raised or that you hear me speaking quietly until I forbid you.
لِي رَسُولُ اللَّهِ ﷺ إِذْنُكَ عَلَىَّ أَنْ يُرْفَعَ الْحِجَابُ وَأَنْ تَسْتَمِعَ سِوَادِي حَتَّى أَنْهَاكَ