Keepers of the Covenant - Restoration Chronicles Series by Lynn Austin and published by Bethany Books.
In one life-changing moment, the lives of the Jewish exiles in Babylon are thrown into confusion and despair when a decree arrives from the king's palace in Susa. It calls for the annihilation of every Jewish man, woman, and child throughout the empire on the thirteenth day of Adar, in less than one year. Ezra, a quiet Jewish scholar and teacher, is suddenly called upon to lead the community as they seek God for a reason for this catastrophe. When a second decree arrives, authorizing them to fight back, Ezra is thrust into the role of military leader as they defend themselves against their enemies.
When the battles come to an end, Ezra's brother Jude is dead and Ezra is required by the Law he so diligently studies to marry Jude's widow, Devorah, and provide an heir. Fatherhood changes Ezra, and he asks God to make a way for him and the other exiles to leave Babylon for good and return to Jerusalem. His prayers are answered and the exiles move to Judea to revitalize worship at the temple--but the fight to keep God's Law is never easy. As more and more of his community are tempted, a new battle emerges...this one for the survival of God's covenant and the souls of His chosen faithful.