Jesus Begins To Establish The Basis Of His New Community (4:18-22).
Jesus' plan for the future now begins to unfold. He begins to call men to follow Him, men whom He can instruct and train, with the intention of them becoming ‘fishers of men'. He already has in mind His new community (His congregation of the new Israel - Matthew 16:18) The first ones that He called, as far as Matthew is concerned, were men whom He already knew, men who had served with Him while He Himself was supporting John the Baptiser, and who had come back to Galilee with Him earlier. (Philip may well, however, have also been with Him, as described in John 1:43).
The calling of these four symbolises the call of all His disciples. They are probably mentioned because of their importance, for Peter, James and John are regularly selected out for special experiences (Mark 5:17 - Jairus' daughter; Matthew 17:1 - the Transfiguration, Matthew 26:17 - in Gethsemane). But we learn later that others are called on to follow Him in the same way, men such as Matthew (Matthew 9:9), an unknown disciple (Matthew 8:22) and (unsuccessfully) the young man (Matthew 19:21). We are probably to see these as examples of what must have included many others (compare Matthew 8:19; Luke 8:2; Luke 9:57-62).
We should note that Jesus method of seeking out the disciples who would become prominent, rather than waiting for them to approach Him, parallels Elijah's call of Elisha. In the case of Elisha, Elijah sought him out and called him to follow him, and Elisha then did leave all and follow him, having first said goodbye to those at home, and having destroyed any temptation to return home (1 Kings 19:19-21). This copying of Elijah, but in more abundance, may suggest that He saw His disciples as intended to be the prophets of the new era.