Scott Hafemann, The God of Promise and the Life of Faith. Crossway Books, 2001, p. 203.
The difficulty of the commands is merely a reflection of the greatness of the Gospel. Jesus’ expectation is built on his anticipation of what God will do in the lives of His people! Jesus demands the humanly impossible precisely because His provisions are supernatural. The magnitude of Jesus’ commands must mean, therefore, that they are tied to the grandest promise of all, namely, the promise that God himself will work in every circumstance to conform us to the image of Christ (Romans 8:28-29).
Scott Hafemann, The God of Promise and the Life of Faith. Crossway Books, 2001, p. 203.