This is a somewhat macabre narrative.  Peter assumes the leadership role, as he had often done before (Luke 9:33; John 21:3).  This time, Peter was concerned that the absence of Judas Iscariot, who died after betraying Jesus, would frustrate Jesus' plan of having 12 apostles (Luke 6:13-16).  Gathering about 120 believers, including his fellow apostles, Peter invited them to choose a replacement.  However, this was not just a matter of voting for friends; it was treated as a very serious matter.  The man must have known Jesus and have been a part of His 'team' all the time from the time John baptised Him until His ascension. The chosen man must also have personally encountered Jesus after the resurrection.

Two men qualified, Joseph and Matthias.  They were obviously well known and equally respected.  The apostles trusted their characters and their devotion to Jesus.  So, which were they to choose?  They only wanted Jesus' choice; after all, all the apostles had been appointed to be His witnesses (Acts 1:8).  And so, they prayed.  They knew that they had to make a decision, but were suspicious of the motivation of their own hearts (Jeremiah 17:9).  Peter was all too aware that he also betrayed his relationship with Jesus by denying that he knew his Master (Luke 22:60-62).

Matthias was appointed, but neither the Bible nor the church fathers ever mention him again.  [Many consider that the Apostle Paul was the 12th apostle as he suggests (1 Corinthians 15:7-10)].  The casting of lots was not to give the two men an equal chance of being appointed.  It was to give the Lord the right to say which man He wanted.  In the absence of the Holy Spirit's direct inspiration, Old Testament leaders used this apparently random method to make decisions (Joshua 18:6-10). Proverbs 16:33 says, “The lot is cast into the lap, but its every decision is from the LORD".  The Holy Spirit was given a few days after this event, and the church never again used 'lots' to make decisions, nor did Jesus commend that style of decision-making.

Making decisions is the basis of personality.  Self-centred decisions are the essence of sin.  Making godly decisions requires us to work with Him - not just to get the right answer, but to learn to be the right people.  Before the Holy Spirit was given to the church, only a few people knew God's heart (some prophets, priests and kings ... and many of them squandered that privilege).  But now, God has given His Holy Spirit to every believer (Romans 8:9).  We now have God's Spirit to help us to interpret God's Word and lead us into all truth (John 16:13).  So, every decision we make needs prayerful consideration, distrustful of our own heart-motivation and being willing for the Lord to show us the right way.  Then we must obey and do it because every godly decision must be put into action at the right time.