But, as for the soul itself, it sometimes happens that the soul of an infinitely lofty person comes to be the son of a despised and lowly man. …
Not only is this possible, but some great and lofty souls cannot be born any other way. …
Moses was born from the marriage of Amram with his aunt, Yocheved; although this was a permissible union at the time, following the giving of the Torah, it is counted among the most severe of incestuous relationships.
But the most markedly dubious ancestry is that of the Messiah. His is an ancestry that includes the unions of Judah and Tamar, Boaz and Ruth, David and Bathsheba, Solomon and Naamah the Ammonite.
The soul of David, which is the fourth leg of the “divine chariot,” and the soul of the Messiah, which is “lofty, exalted, and exceedingly high,” are the loftiest of souls but are imprisoned in the depths of kelipah and have to pass through the twilight zone between holiness and profanity to be extracted from captivity.
They are like pearls that lie buried in refuse heaps.
—Rabbi Adin Steinsaltz