That it is impossible to attain to God the Father, except by His Son Jesus Christ
In the Gospel: “I am the way, and the truth, and the life: no one comes to the Father but by me.” Also in the same place: “I am the door: by me if any man shall enter in, he shall be saved.” Also in the same place: “Many prophets and righteous men have desired to see the things which you see, and have not seen them; and to hear those things which you hear, and have not heard them.” Also in the same place: “He that believes in the Son has eternal life: he that is not obedient in word to the Son has not life; but the wrath of God shall abide upon him.” Also Paul to the Ephesians: “And when He had come, He preached peace to you, to those which are afar off, and peace to those which are near, because through Him we both have access in one Spirit unto the Father.” Also to the Romans: “For all have sinned, and fail of the glory of God; but they are justified by His gift and grace, through the redemption which is in Christ Jesus.” Also in the Epistle of Peter the apostle: “Christ has died once for our sins, the just for the unjust, that He might present us to God.” Also in the same place: “For in this also was it preached to them that are dead, that they might be raised again.” Also in the Epistle of John: “Whosoever denies the Son, the same also has not the Father. He that confesses the Son, has both the Son and the Father.”
Source: The Treatises of Cyprian (New Advent)