15In those days Peter stood up among the brothers (the company of persons was in all about 120) and said, 16“Brothers, the Scripture had to be fulfilled, which the Holy Spirit spoke beforehand by the mouth of David concerning Judas, who became a guide to those who arrested Jesus. 17For he was numbered among us and was allotted his share in this ministry.” 18(Now this man acquired a field with the reward of his wickedness, and falling headlong he burst open in the middle and all his bowels gushed out. 19And it became known to all the inhabitants of Jerusalem, so that the field was called in their own language Akeldama, that is, Field of Blood.) 20“For it is written in the Book of Psalms, “‘May his camp become desolate,
and let there be no one to dwell in it’; and “‘Let another take his office.’21So one of the men who have accompanied us during all the time that the Lord Jesus went in and out among us, 22beginning from the baptism of John until the day when he was taken up from us—one of these men must become with us a witness to his resurrection.” 23And they put forward two, Joseph called Barsabbas, who was also called Justus, and Matthias. 24And they prayed and said, “You, Lord, who know the hearts of all, show which one of these two you have chosen 25to take the place in this ministry and apostleship from which Judas turned aside to go to his own place.” 26And they cast lots for them, and the lot fell on Matthias, and he was numbered with the eleven apostles.

In this section we see Peter emerging as the leader within the group. Indeed, Peter’s ministry dominates the first part of this book (Chs.1-12), before the focus turns to Paul’s ministry (13-28).

The necessity to replace Judas was based on an understanding of Scripture. It had to happen because the Holy Spirit had spoken through a human mouth. God’s Word has to have the final say in all things. It is important to emphasise that they looked to God to guide them. They wanted His choice (24). God knows everything – not just the outside of a person but also the inside. A leader’s ”heart” is of paramount importance. We do not find this method of guidance employed again after Pentecost, but let’s be clear that they sincerely sought God’s choice.

‘If we are faithful to read God’s Word, study it, meditate on it, and obey it, God will guide us when we have decisions to make…The Holy Spirit uses truth; not ignorance; so the more facts we have, the better. We should use our common sense but not lean on it (Prov.3:5-6), for we walk by faith and not by sight. If we sincerely move in the wrong direction, the Lord will show us (Acts 16:6-10; Phil.3:15), so we need not fear. It is good for believers to read the Word and pray together as they seek the mind of the Lord.’ Warren Wiersbe