Why would Matthew use the sentence "When Jesus finished these words" as his section divider?

Here, we not only find the ending c/f "When Jesus ended these words", but within the text and just before this statement one word sums up a step by step process taking place within the section towards true discipleship.

Thus in the Gospel of Matthew we find many of the stories in Mark are being repeated. But at the same time the presentation is changed to give a much greater emphasis on the passage of time and a spiritual development taking place within the disciples.

Section A
Ch1:1-4:25 (then)




Section B
5:1-7:23 (then)


Section C
8:1-10:42 (then)


Section D
11:2-18:35


Section E
19:3-25:46


Section F
26:1-28:20