Midrash for Bava Metzia 118:14
תניא רבי אליעזר הגדול אומר מפני מה הזהירה תורה בל"ו מקומות ואמרי לה במ"ו מקומות בגר מפני שסורו רע
It has been taught: R. Eliezer the Great said: Why did the Torah warn against [the wronging of] a proselyte in thirty-six, or as others say, in forty-six, places? Because he has a strong inclination to evil.<span class="x" onmousemove="('comment',' So Rashi in Hor. 13a. Jast.: because his original character is bad — into which evil treatment might cause him to relapse. ');"><sup>24</sup></span> What is the meaning of the verse,<i> Thou shalt neither wrong a stranger, nor oppress him; for ye were strangers in the land of Egypt</i>? It has been taught: R. Nathan said: Do not taunt your neighbour with the blemish you yourself have.<span class="x" onmousemove="('comment',' Thus be translates the verse: Do not wrong a proselyte by taunting him with being a stranger to the jewish people seeing that ye yourselves were strangers in Egypt. ');"><sup>25</sup></span>