What is going on when the Bible mentions casting lots?
A simple word study in both the Hebrew and the Greek shows us that the term comes from a variety of different words. It would be like if we said "draw straws," flip a coin," or "played rock-paper-scissors." As a reader you get the idea what we were doing even if the procedure was as different as the words we use. And the practice was as different as shaking arrows to looking a livers (Ezekiel 21:21), to tossing stones in the lap (Proverbs 16:33).
They cast lots on a few occasions in the Bible. It's found in both the Old and New Testaments. Here are a some locations where you can read about lot casting: Leviticus 16:8; Joshua 18:6-10; 1 Chronicles 24:31; 1 Chronicles 25:8; 1 Chronicles 26:13–14; Nehemiah 10:34; Nehemiah 11:1; Esther Esther 3:7; 9:24; Job 6:27; Psalm 22:18; Joel 3:3; Obadiah 1:11; Jonah 1:7; Luke 23:34; John 19:24; and Acts 1:26.
At times, it seems casting lots was acceptable to God, even commanded at times. (Numbers 26:55; 33:54; 34:13; 36:2). God allowed it to determine his will. Remember when the disciples replaced Judas (Acts 1:26)? Or when the Israelites were dividing up the land (See Joshua 18 for example)? In Nehemiah 11:1, we read that they cast lots to determine who would live in the city and who would remain out in the country. Dr. Charles Fensham says that Nehemiah might have been practicing leadership wisdom having them cast lots in Nehemiah 11. In his commentary titled, The Books of Ezra and Nehemiah (Eerdmans, 1982) he writes, "By casting the lot it is no longer Nehemiah who forces them to live in Jerusalem, but it is the will of God. So they could not bear a grudge against him" (243). And we see non-believers casting lots, such as the sailors who wanted to know who caused the storm in Jonah (Jonah 1:7) and the soldiers that divided Jesus garments (Matthew 27:35).
Should we cast lots today?
Well, if we're honest, many of us already "cast lots" from time to time. It's like flipping a coin or playing rock-paper-scissors to determine who has to change the baby's diaper or run to the store to get milk. We don't get too concerned when a referee cast lots to see which team will kick off first or when we roll dice to determine who will go first in Monopoly. However, we don't see it practiced in the Bible after God sent the Holy Spirit in Acts 2. In matters of spiritual discernment, we have the Holy Spirit to guide us. As we seek God's will, we have much more to go on than the flip of a coin or the casting of lots.