I say, and with God's success: It is disliked to perform voluntary prayers after the Fajr prayer, unlike when one prays a missed obligatory prayer, a prostration of recitation, or a funeral prayer; because the prohibition is for a reason outside of the time, which is to treat the time as if it were occupied with the obligatory prayer of the time, which is better than actual voluntary prayers. Thus, it does not appear in the case of another obligatory prayer like it. The evidence that the prohibition is for something else is that it does not prevent the obligatory prayer of one time from being performed at the end of another time; if it were for its own sake, it would have been prevented, unlike the three previously mentioned times. Abu Sa'id Al-Khudri (may Allah be pleased with him) reported that the Prophet (peace be upon him) said: "There is no prayer after the Asr prayer until the sun sets, and there is no prayer after the Fajr prayer until the sun rises," in Sahih Muslim 1: 567, and Sahih Bukhari 1: 400. Refer to: Al-Tabeen 1: 87, and Al-Waqayah p. 138, and Allah knows best.