On Prayer by Tertullian
Chapter XI.--When Praying the Father, You are Not to Be Angry with a Brother.
That we may not be as far from the ears of God as we are from His precepts, the memory of His precepts paves for our prayers a way unto heaven; of which precepts the chief is, that we go not up unto God's altar before we compose whatever of discord or offence we have contracted with our brethren. For what sort of deed is it to approach the peace of God without peace? the remission of debts while you retain them? How will he appease his Father who is angry with his brother, when from the beginning |all anger| is forbidden us? For even Joseph, when dismissing his brethren for the purpose of fetching their father, said, |And be not angry in the way.| He warned us, to be sure, at that time (for elsewhere our Discipline is called |the Way| ), that when, set in |the way| of prayer, we go not unto |the Father| with anger. After that, the Lord, |amplifying the Law,| openly adds the prohibition of anger against a brother to that of murder. Not even by an evil word does He permit it to be vented. Ever if we must be angry, our anger must not be maintained beyond sunset, as the apostle admonishes. But how rash is it either to pass a day without prayer, while you refuse to make satisfaction to your brother; or else, by perseverance in anger, to lose your prayer?