“Adam was further intimate with his wife and she gave birth to a son, and she called his name Seth: As God has provided me with another offspring in place of Abel, as Cain killed him” (Genesis 4:25). “Adam was further intimate with his wife,” extra desire was added for him to his desire. In the past, when he did not see her, he would not desire her. Now, whether he saw her or did not see her, he desired her.
Rabbi Abba bar Yudan in the name of Rabbi Aḥa: This is an allusion for seafarers, that they will eventually remember their homes and come immediately. “She called his name Seth [Shet]: As God has provided [shat] me with another offspring.” Rabbi Tanḥuma said in the name of Rabbi Shmuel: She was looking ahead at that offspring who would come from a different place. Who is that?
It is the messianic king.16The Messiah, like all mankind, will descend from Seth, and he will set up the foundations (mashtit) for a new world. The Messiah comes “from a different place” in that he is of non-Jewish descent, from David, who descended from Ruth the Moavite. “In place of Abel, as Cain killed him.” Due to the sin of [killing] Abel, Cain was killed.17The verse could also be translated, “as Abel killed Cain.”
This is analogous to two trees that were adjacent to one another. The wind felled one of them, and it fell on its neighbor and felled it. So, “in place of Abel, as Cain killed him” – due to the sin of [killing] Abel, Cain was killed.