Makkot, Chapter Two, Mishnah Five
Mishnah five discusses the making of roads to lead to the cities of refuge and the accompaniment of the manslayer as he makes his way.
1) And direct roads were made leading from one to the other, as it says, You shall prepare the way and divide the borders of your land into three parts (Deut. 19:3).
2) And they delegate to him to disciples of the Sages [as escorts] in case anyone attempted to slay him on the way, and that they might speak to him.
a) Rabbi Meir says: He may [even] plead his cause himself, as it says, And this is the word of the manslayer (Deut. 19:4).
Section one: Roads were to be made leading to the cities of refuge so that the manslayer would not have a difficult time finding his way. Remember that if the blood avenger found him before he arrived at the city of refuge he could kill him without incurring penalty.
Section two: In order to prevent the blood avenger from finding the manslayer on his way to the city of refuge the court would assign two disciples of the Sages to travel with him and plead with the blood avenger should he try and attack while on the way. Rabbi Meirs statement can be read in two ways. He may be suggesting that not only should the disciples of the Sages plead his case, but he should plead himself. According to this interpretation, Rabbi Meir does not disagree with the previous opinion, but rather adds upon it. Alternatively, Rabbi Meir may disagree with the previous opinion. Rabbi Meir may believe that only the manslayer may plead his case, but not the disciples of the Sages. In either case the act of pleading is learned from the verse in Deuteronomy which states the word of the manslayer, understood by Rabbi Meir to hint that the manslayer should plead his own case.