Augustine of Hippo
Catena Aurea · Matthäusevangelium 5
For I say unto you, That except your righteousness shall exceed the righteousness of the Scribes and Pharisees, ye shall in no case enter into the kingdom of heaven. Ye have heard that it was said by them of old time, Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment: But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.
(Id. cont. Faust. xix. 31.) This expression, the kingdom of heaven, so often used by our Lord, I know not whether any one would find in the books of the Old Testament. It belongs properly to the New Testament revelation, kept for His mouth whom the Old Testament figured as a King that should come to reign over His servants. This end, to which its precepts were to be referred, was hidden in the Old Testament, though even that had its saints who looked forward to the revelation that should be made.