The Church Fathers on the Perseverance of the Saints

 

"Satan will not be at liberty to do anything against the servants of the living God unless the Lord grant leave, either that He may overthrow Satan himself by the faith of the elect which proves victorious in the trial, or in the face of the world show that apostatizers to the devil's cause have been in reality His servants." (Tertullian, De Fuga in Persecutione, 2)

"Whence, moreover, nothing can separate the Church— that is, the people established in the Church, faithfully and firmly persevering in that which they have believed— from Christ, in such a way as to prevent their undivided love from always abiding and adhering." (Cyprian, Epistle 62 to Caecilius, section 13)

"You have written also, that on my account the Church has now a portion of herself in a state of dispersion, although the whole people of the Church are collected, and united, and joined to itself in an undivided concord: they alone have remained without, who even, if they had been within, would have had to be cast out. Nor does the Lord, the protector of His people, and their guardian, suffer the wheat to be snatched from His floor; but the chaff alone can be separated from the Church," (Cyprian, Epistle 68 to Florentius Pupianus, section 8)

"yet that the Church which believes on Christ, and holds that which it has once learned, never departs from Him at all, and that those are the Church who remain in the house of God; but that, on the other hand, they are not the plantation planted by God the Father, whom we see not to be established with the stability of wheat, but blown about like chaff by the breath of the enemy scattering them, of whom John also in his epistle says, They went out from us, but they were not of us; for if they had been of us, no doubt they would have continued with us. 1 John 2:19" (Cyprian, Epistle 54 to Cornelius, section 7)

"He says that the man of God and the worshipper of God, depending on the truth of his hope, and Corroded on the steadfastness of his faith, is not moved by the attacks of this world and this life" (Cyprian, Treatise 5: An Address to Demetrianus, section 20)

"He, that has chosen the narrow and laborious way, before the smooth and easy one, shall not see everlasting corruption: namely, the affliction that shall endure for ever." (Basil of Caesarea, Homily on Psalm 48)