The casting of lots to make a decision between two candidates was an entirely proper procedure (see Proverbs 16:33). Typically it would involve names being written on stones, placing the stones in a container, and then shaking the container until one stone fell out.1 In this instance it serves to affirm that Jesus Christ must reveal his choice to the gathering, just as he chose in the past (Luke 6:12–16; Acts 1:2).2
26 And they cast lots for them, and the lot fell on Matthias, and he was numbered with the eleven apostles.