en_tn_condensed/exo/24/06.md

Moses took half of the blood and put it into basins

Moses collected half of the blood in basins in order to splash it on the people in Exodus 24:8. This would confirm the people's participation in the covenant between the people of Israel and God.

he sprinkled the other half onto the altar

Here the altar represents God. This would confirm God's participation in the covenant between God and the people of Israel.