Christ showed man the perfect will of God by demonstrating the perfect nature of God and the mature nature of man. (religion-online.org)
What Jesus meant by a righteousness exceeding that of the scribes and Pharisees (5:20) was a thoroughgoing effort to obey the revealed will of God according to its inmost intent, not because every item was explicitly commanded or could be logically deduced from the sacred text, but because one's own conscience and judgment responded to the underlying principle of it all. (religion-online.org)
mary was chosen because God could count on her to let jesus grow up in his own way, that she would be available to him as a helper when needed, and that she would not prevent the austere will of God from being fulfilled in her son's life. (nakedpastor.com)