Return to Me by Lynn Austin
After years of watching his children and grandchildren wander from their faith, Iddo's prayers are answered: King Cyrus is allowing God's chosen people to return to Jerusalem. Jubilant, he joyfully prepares for their departure, only to learn that his family, grown comfortable in the pagan culture of Babylon, wants to remain.
Zechariah, Iddo's oldest grandson, feels torn between his grandfather's ancient beliefs and the comfort and success his father enjoys in Babylon. But he soon begins to hear the voice of God, encouraging him to return to the land given to his forefathers.
Restoration Chronicles Series, Book #1