9. I am become a stranger to my brethren, and an alien to the sons of my
mother. He calls the Jews here brethren for they were joined to Him by
proximity of blood; He became a stranger to them when they refused to show
belief in Him. He was Himself descended from the seed of Abraham in the flesh,
but they were disinherited by their evil deeds and divorced from their
connexion with the patriarch. As Christ says in the gospel, If you were the sons of Abraham, you would
have done the works of Abraham. He added: And an alien to the sons of my mother. We term as alien any person
dwelling temporarily in our house who is received not through
blood-relationship but as a foreigner. By His mother He means the synagogue,
from which He was sprung when He deigned to be born of the Jewish race. He
calls sons of His mother those whom He earlier described as His brethren; but
these sons, if they had been truly sons, would not have regarded the Lord
Christ as an alien, but would have received Him as a most dear brother. (Cassiodorus,
Commentary on Psalm 68, in Explanation of the Psalms, 3 vols. [trans.
P. G. Walsh; Ancient Christian Writers 52; New York: Paulist Press, 1991], 2:146-67)
