I need an explanation of the last sentence of the hadith mentioned below. How authentic it is?
Allah's Apostle (Sallallahu 'Alaihi Wa Sallam) said, "When the (upper) edge of the sun appears (in the morning), don't perform a prayer till the sun appears in full, and when the lower edge of the sun sets, don't perform a prayer till it sets completely. And you should not seek to pray at sunrise or sunset for the sun rises between two sides of the head of the devil (or Satan)." (Bukhārī, 494)
The best possible interpretation of the tradition is that the fellows of satan try to come between the sun and the people worshipping it so as to make them prostrate before him as well. The horns symbolize Satan's parties. Many people would worship the sun at the time of advent of Islam. Like many other things praying at the time of sunrise has been prohibited for Muslims to avoid identity with those false religions and the worship rituals they taught.