Irenaeus

In his own words on Jude

• Jude 1:3

  True knowledge, then, consists in the understanding of Christ, which Paul terms the wisdom of God hidden in a mystery, which "the natural man receiveth not," the doctrine of the cross; of which if any man "taste," he will not accede to the disputations and quibbles of proud and puffed-up men, who go into matters of which they have no perception. For the truth is unsophisticated; and "the word is nigh thee, in thy mouth and in thy heart," as the same apostle declares, being easy of comprehension to those who are obedient. For it renders us like to Christ, if we experience "the power of his resurrection and the fellowship of His sufferings." For this is the affinity of the apostolical teaching and the most holy "faith delivered unto us," which the unlearned receive, and those of slender knowledge have taught, not "giving heed to endless genealogies," but studying rather [to observe] a straightforward course of life; lest, having been deprived of the Divine Spirit, they fail to attain to the kingdom of heaven. For truly the first thing is to deny one's self and to follow Christ; and those who do this are borne onward to perfection, having fulfilled all their Teacher's will, becoming sons of God by spiritual regeneration, and heirs of the kingdom of heaven; those who seek which first shall not be forsaken.

  Fragments from the Lost Writings of Irenaeus

• Jude 1:6-7

  Since the Son of God is always one and the same, He gives to those who believe on Him a well of water [springing up] to eternal life, but He causes the unfruitful fig-tree immediately to dry up; and in the days of Noah He justly brought on the deluge for the purpose of extinguishing that most infamous race of men then existent, who could not bring forth fruit to God, since the angels that sinned had commingled with them, and [acted as He did] in order that He might put a check upon the sins of these men, but [that at the same time] He might preserve the archetype, the formation of Adam. And it was He who rained fire and brimstone from heaven, in the days of Lot, upon Sodom and Gomorrah, "an example of the righteous judgment of God," that all may know, "that every tree that bringeth not forth good fruit shall be cut down, and cast into the fire."

  Against Heresies Book IV