a sin offering for all Israel of twelve male goats: This blood sacrifice brought God's forgiveness for unintentional sins, ceremonial uncleanness, or thoughtless wrong acts (Leviticus 4–5). Similar sacrifices were made when Moses dedicated the tabernacle (Numbers 7) and when Solomon dedicated the first temple (2 Chronicles 7:1, 4).
one for each tribe of Israel: Although most returnees were from Judah and Benjamin (Ezra 1:5; 4:1), people from the priestly tribe of Levi are also mentioned (1:5; 2:40, 70). It is also likely that there were returnees from some of the ten northern tribes of Israel. Even if all tribes were not physically represented, the twelve sacrifices emphasized the desire for God to maintain his covenant relationship with all Israel.