The Kingdom of Israel was the northern kingdom, formed of the 10 tribes. The southern Kingdom of Judah was made up the tribe of Judah (predominantly) along with Benjamin and some Levites. Many from the northern kingdom fled south and mixed with the population of Judah. By the first century C.E., there was no real tribal distinction remaining with the exception of the priestly class.
All right, then. I have it totally backwards.
Notwithstanding, the ministry of Jesus and His Apostles before the Resurrection was focused on thedescendants of Abraham in this geopgraphic region. They did not go out and about to foreign lands.
SD