1. When our Lord and Master Jesus Christ said, “Repent” [Matt. 4:17], he willed the entire life of believers to be one of repentance.
2. This word cannot be understood as referring to the sacrament of penance, that is, confession and satisfaction, as administered by the clergy.
3. Yet it does not mean solely inner repentance; such inner repentance is worthless unless it produces various outward mortifications of the flesh.”
Martin Luther, “Nintey-Five Theses,” in Luther’s Works, Vol. 31: Career of the Reformer I, ed. Jaroslav Jan Pelikan, Hilton C. Oswald, and Helmut T. Lehmann (Philadelphia: Fortress Press, 1999), 25.

Pennington challenges the commonly accepted idea that in Matthew’s phrase “kingdom of heaven,” “heaven” stands as a reverential circumlocution for God. He notes that though this view is commonly stated in virtually all commentaries on Matthew, it rests on a single article by Gustaf Dalman, which is methodologically problematic. It is difficult to establish from contemporary writings that the Jews consistently or widely adopted reverential circumlocutions for God.
Stuart, Douglas K. 
Hamilton, Victor P. 