Yesterday I posted a piece on Avot 5:22, which contrasted the qualities exemplified by Abraham and Balaam and, by extension, by those who follow them.
Why does this Mishnah pick Abraham as the gold standard by which to evaluate Balaam and find him lacking? Would not Moses have been a better measure of comparison? There is nowhere any suggestion that Moses was deficient in the three areas of excellence associated here with Abraham: he too had a generous outlook (Shemot 32:30-32), a meek spirit (Chullin 89a) and a humble soul (Bemidbar 12:3). He was an exact contemporary of Balaam, while Abraham lived six generations earlier. Both Moses and Balaam had top-class prophetic talents (Bemidbar Rabbah 14:20; Berachot 7a). Further, the placing of this mishnah within the fifth perek almost invites comparison with Moses rather than Abraham: whereas the other mishnayot dealing with Abraham and his exceptional qualities come right at the beginning of this perek, the only other mishnah in it which deals with Moses is found immediately preceding this one.
Because this mishnah is dealing with middot (character traits and qualities) rather than mitzvot and averot (positive and negative commands), we may have an answer. There is a qualitative difference between those who lived before the Giving of the Torah at Sinai and those who lived subsequently.
Before Sinai, there were two measures of a man’s worth: one was in the way he developed and acted in accordance with his personal qualities, the other being his adherence to the seven Noahide Laws to which all of mankind is universally subject. After the Giving of the Torah, the Jewish people could also be measured in terms of their service to God through the performance of mitzvot and the avoidance of averot that were revealed at Sinai. By comparing Abraham with Balaam, this mishnah compares like with like, contrasting two personalities who were ostensibly playing by the same Noahide rules.
There is another possible answer. Balaam is quite conscious of the role played by the Patriarchs Abraham, Isaac and Jacob in securing a permanent relationship between God and the Children of Israel. He makes a great show of setting himself up as being their equal. The Patriarchs between them built seven altars on which to make offerings before God, so Balaam instructs Balak to do likewise on the assumption that he must exceed or at least equal the performance of the Patriarchs if he is to obtain a chance to break the bond they had forged with God. Since Balaam is seeking to undermine the covenant first made with Abraham and only later confirmed with his descendants, it is with Abraham and not Moses that Balaam is to be compared.
The appropriate nature of the Abraham-Balaam comparison is suggested by two further considerations. The first, which appeals to scholarship, is the intertextuality of the stories of the Akedah, where Abraham is ordered to sacrifice his son Isaac, and the engagement of Balaam to destroy the Jewish people. Both Abraham and Balaam saddle their asses early in the morning and take two lads with them; both are stopped by an angel before killing their companion. In both episodes they climb mountains and there is a burnt offering. Finally, both episodes end with a blessing for the Jewish people.
The second consideration appeals to our affection for symmetry and balance: Abraham is the righteous person who appeals to God in order to save a wicked people from destruction, while Balaam is the wicked person who appeals to God in order to achieve the destruction of a righteous people. Further, while Balaam seeks a generous reward for cursing the Children even though he fails in this mission, Abraham spurns a generous reward that is his for the taking after he secures the defeat of the Five Kings.