That we are to live with the good, but to avoid the evil
In Solomon, in the Proverbs: “Bring not the impious man into the habitation of the righteous.” Also in the same, in Ecclesiasticus: “Let righteous men be your guests.” And again: “The faithful friend is a medicine of life and of immortality.” Also in the same place: “Be far from the man who has the power to slay, and you shall not suspect fear.” Also in the same place,: “Blessed is he who finds a true friend, and who speaks righteousness to the listening ear.” Also in the same place: “Hedge your ears with thorns, and hear not a wicked tongue.” Also in the seventeenth Psalm: “With the righteous You shall be justified; and with the innocent man You shall be innocent; and with the froward man You shall be froward.” Also in the first Epistle of Paul to the Corinthians: “Evil communications corrupt good dispositions.”
Source: The Treatises of Cyprian (New Advent)