Not as Cain, who was of that wicked one, and slew his brother. And why slew he him? Because his own works were evil, and his brother's righteous.
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Augustine of Hippo
AD 430
Therefore, where envy is, brotherly love cannot be. Mark, my beloved. He that envies, loves not. The sin of the devil is in that man; because the devil through envy cast man down. For he fell, and envied him that stood. He did not wish to cast man down that he himself might stand, but only that he might not fall alone. Hold fast in your mind from this that he has subjoined, that envy cannot exist in charity. You have it openly, when charity was praised, Charity envies not. 1 Corinthians 13:4 There was no charity in Cain; and had there been no charity in Abel, God would not have accepted his sacrifice. For when they had both offered, the one of the fruits of the earth, the other of the offspring of the flock; what think ye, brethren, that God slighted the fruits of the earth, and loved the offspring of the flock? God had not regard to the hands, but saw in the heart: and whom He saw offer with charity, to his sacrifice He had respect; whom He saw offer with envy, from his sacrifice He t...
Not as Cain. For he loved himself only, and hated his brother because he saw that his offering was acceptable to God. As God says to Cain (according to LXX), "Hast thou not sinned, if thou offerest rightly, but dividest not rightly?" "For Cain did this," says S. Augustine (de Civ. xv7), "giving to God something which was His, but gratifying himself. Which," says Hebrews , "all who do not follow the will of God, but their own will, and in their perversity of heart make Him an offering with which they think He can be bought off, and this too even to gratify their depraved desires." And accordingly Eusebius (de Præp. xi4) says that he was appositely called Cain from the Hebrew word kana to envy. See S. Gregory, Mor. x6; S. Chrysostom, in Matthew 18, where he speaks of nine degrees of love; and S. Augustine (de Doct. Christ, i22), who says, "The rule of love is laid down by God. And in saying "the whole heart," &c, He left no portion of our life unemployed, and left no room for the enjoyme...