In the Hebrew Bible the Urim and Thummim is a phrased used that is associated with the sacred breast plates which were used for divination. Leviticus 19:26 says not to practice divination. How do I make sense of this apparent contradiction?
The Urim and Thummin were used when asking God for answers. Divination gets answers elsewhere. Therefor there is a difference in intent.
Rather like how praying to God is fine, whereas praying to Jupiter or Zeus or one of the Egyptian gods is wrong.
The RSV-CE translation specifies the divination that is forbidden:
Lev 19:26 …You shall not practice augury or witchcraft.
Why is this practice no longer used?
Because we now have the Holy Spirit in the Church to lead us into all truth. The last time the Bible mentions the casting of lots was before Pentecost, when the apostles elected Matthias to replace Judas Iscariot. After that, the Holy Spirit guided the Church directly.
Casting lots is not related to that practice. “We” still cast lots today, to get our Popes.
Well, yes and no. Of course, the casting of lots in Acts 2 wasn’t Urim and Thummim of course, but the principle is similar. But for the Pope, we don’t strictly cast lots. We elect.
As I recall Urim and Thummim were indeed a way to learn God’s will, however exactly what it was or how it was done is no longer known.