These verses lead into Christ's teaching on false prophets. From its context, it appears that Jesus says that false ministers will neither acknowledge or teach the narrow way that leads to life, the narrow way that leads to persecution. Instead, they will do just what God shows the Old Testament false prophets did: They will teach "peace, peace"—the smooth, easy, and broad way.
In other words, they will teach that Christians need make no sacrifices in their obedience to God. It is so interesting that, in the last few years in the church, so many things have been liberalized. Are we getting away from the straight and the narrow, the difficult and the sacrificial way?