This reading that Catholics have today is wise words influenced by the cultural environment of Greece in Alexandria, Egypt. You have the ability to make choices given you by God; So you must choose the sort of person you want to be in your condition and situation!
In his writings Paul draws upon his own Graeco-Roman education together with the revelation that he has recieved from God. Here he tells of a wisdom that comes from the very Spirit of God – the Spirit that we must let influence our lives too!
Matthew respects the value of the Jewish Law recieved from God, but we listen to a selection from Chapter 5 where he wants to tell his readers that with Jesus we should interpret the Law in the deeper way that Jesus did in His life here; we must let this be the way we try to live.
Further comment can be found here.