Mishkat al-Masabih #3742

He told that when the Prophet came to Medina he slew a camel or a cow.* * There seems to be no certainty as to whether this refers to the arrival at the time of the Hijra, or whether the tradition means to indicate a general practice. It is said that the sunna requires one who returns from a journey to provide such entertainment as is within his means. If the use of "or” in the tradition does not indicate a doubt on the part of the transmitter as to which word is correct, but is a real alternative, this would justify the view that the tradition speaks of a practice of the Prophet. But the Arabic construction really suggests one occasion rather than any time the Prophet came back to Medina. Bukhari transmitted it.