Quoting from article...

When he was still a young theologian, Joseph Ratzinger studied the thinking of Tyconius, a theologian of the fourth century, who said that the body of the Church is divided into a dark and evil church and a righteous one. In the present state, the two bodies of the Church are inseparably commingled, but they will divide at the end of time.

The Church, the future pope wrote in 1956, is until the Last Judgment both the Church of Christ and the Church of the Antichrist: “The Antichrist belongs to the Church, grows in it and with it up to the great separation, which will be introduced by the ultimate revelation.”

My comments...

Jesus indeed taught this. Matthew 13...

The Parable of the Wheat and the Tares

24 Another parable He put forth to them, saying: “The kingdom of heaven is like a man who sowed good seed in his field; 25 but while men slept, his enemy came and sowed tares among the wheat and went his way. 26 But when the grain had sprouted and produced a crop, then the tares also appeared. 27 So the servants of the owner came and said to him, ‘Sir, did you not sow good seed in your field? How then does it have tares?’ 28 He said to them, ‘An enemy has done this.’ The servants said to him, ‘Do you want us then to go and gather them up?’ 29 But he said, ‘No, lest while you gather up the tares you also uproot the wheat with them. 30 Let both grow together until the harvest, and at the time of harvest I will say to the reapers, “First gather together the tares and bind them in bundles to burn them, but gather the wheat into my barn.” ’ ”