The second quote is based on the Sermon of the Mount, from the Christian gospel book of Matthew (5:17). As to the first quote, the Soncino writes that "There is no passage in any known Gospel that a son and daughter inherit alike."
Modern religious (eg., Steinsaltz) and academic scholars understand the philosopher living near Imma Shalom, who is quoted in the story on Shabbat 116b, as being a Christian sectarian. Writing about the atmosphere of Christian and Jewish polemics in his work Birkat HaMinim: Jews and Christians in Conflict in the Ancient World, Yaakov Teppler presents another indication as to the religious identity of this individual from the text itself. On the philosopher's remark that "Since the day you were exiled from your land, the Torah of Moses was taken away and the avon gilyon was given in its place," Teppler comments:
The Gospel is presented in this source as avon gilyon. This is a scornful play on the Greek word for the gospel, evangelion [the derivation of the English word evangelical]. Avon means sin in Hebrew, so that avon gilyon would be the scripture of sinners, or a scripture which represents the way of a sin.