It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Bilal gives the call to prayer during the night, so keep eating and drinking until Ibn Umm Maktum gives the call to prayer." The narrator says that in fact, Sayyiduna Ibn Umm Maktum (may Allah be pleased with him) was a blind man, he could not see, so he would not give the call to prayer until people said to him, "Give the call to prayer, you have reached the morning."