It is narrated from Hazrat Nawas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: Allah has given an example that there is a straight path, on both sides of which are walls, and in these walls are open doors, with curtains hanging over the doors. At the main gate of the path, a caller is standing and calling out, and another caller is calling from above it. Allah invites to the house of peace and guides whom He wills to the straight path.