Worship at the site of the former Temple begins, and they begin the reconstruction of the Temple. The people don’t want to make the mistake that led to their captivity by failing to worship God. How exciting it must have been for them to return to their land, way of life, and way of worship.
Seventy years is a long time, but God still remembered them and brought them back. It is a miracle that the Jews could still be recognized as a separate people after two generations in Babylon. I’ve heard stories from people of how they were raised without God in their lives, but had faithful grandparents who prayed for them and they were eventually introduced to Jesus. God is faithful!