פירוש על קידושין 139:3

How do we know that mamzerim came with Ezra to Eretz Yisrael? Tobiah comes up to Eretz Yisrael. Tobiah is an Ammonite. He marries Shechaniah’s daughter who is an Israelite. According to our mishnah, the child of a non-Jewish father and a Jewish mother is a mamzer.