"Let no corrupt word proceed out of your mouth, but what is good for necessary edification, that it may impart grace to the hearers. And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. Let all bitterness, wrath, anger, clamor, and evil speaking be put away from you, with all malice. And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you."
John Chrysostom's comments on this passage (Ephesians, Homily 16):
For (Paul) having said, Let all bitterness, and wrath, and clamor, and railing be put away from you, with all malice," he adds, "And be ye kind one to another, tender-hearted, forgiving each other." For all these are habits and dispositions. And our abandonment of the one thing is not sufficient to settle us in the habitual practice of the other, but there is need again of some fresh impulse, and of an effort not less than that made in our avoidance of evil dispositions, in order to our acquiring good ones…
He who is not our enemy, is not necessarily our friend; but there is an intermediate state, neither of enmity nor of friendship, which is perhaps that in which the greater part of mankind stand toward us. He that is not crying is not therefore necessarily also laughing, but there is a state between the two. And so, I say, is the case here. He that is not "bitter" is not necessarily "kind", neither is he that is not "wrathful" necessarily "tender-hearted"; but there is need of a distinct effort, in order to acquire this excellence.
And now look how the blessed Paul, according to the rules of the best husbandry, thoroughly cleans and works the land entrusted to him by the Husbandman. He has taken away the bad seeds; he now exhorts us to retain the good plants. "Be kind", says he, for if, when the thorns are plucked up, the field remains idle, it will again bear unprofitable weeds. And therefore there is need to preoccupy its unoccupied and fallow state by the setting of good seeds and plants. He takes away "anger", he puts in "kindness"; he takes away "bitterness", he puts in "tender-heartedness"; he extirpates "malice and railing", he plants "forgiveness" in their stead.
For the expression, forgiving one another, is this; be disposed, he means, to forgive one another. And this forgiveness is greater than that which is shown in money-matters. For he indeed who forgives a debt of money to him that has borrowed of him, does, it is true, a noble and admirable deed, but then the kindness is confined to the body, though to himself indeed he repays a full recompense by that benefit which is spiritual and concerns the soul; whereas he who forgives trespasses will be benefiting alike his own soul, and the soul of him who receives the forgiveness.