Bart D. Ehrman, The New Testament: A Historical Introduction to the Early Christian Writings, sixth edition (OUP, 2016), 147.
Perhaps the best way to explain Matthew’s extensive criticism of the Jewish authorities is to say that his own community continued to experience opposition from non-Christian Jews, especially influential scribes and rabbis of the local synagogue(s), who accused them of abandoning Moses and the Law, of becoming apostate from the Jewish religion through their ill-advised faith in Jesus.
The Amateur Exegete 