Are there really ten lost tribes of Israel?
No, there is no such thing as ten lost tribes. The ten tribes were not lost and assimilated; they had already returned to Judah before the Babylonian captivity. All Israel went into Babylonian captivity, and all Israel was represented in the return, so by Christ's earthly ministry Jews from every tribe lived in Israel.
Les teaches that when Peter says in Acts 2:36, “let all the house of Israel know assuredly,” there is no such thing as ten lost tribes. He warns not to buy the idea that the ten tribes were lost and assimilated. They were already back down in Judah even for the Babylonian captivity, so all of Israel went into that captivity and all of Israel was represented in those who came back. By the time of Christ’s earthly ministry, Jews from every one of the tribes were living in Israel.