How can the one true church have sinners in it?

The Bible clearly teaches that the Church is composed of both saints and sinners. we see this most indisputably in several parables of Jesus about the kingdom of Heaven(i.e., the Church), such as the wheat or the tares (or weeds), where Jesus teaches that they will grow together until the final judgement, or harvest time(Mt 13:24-30);cf. Mt 3:12) He compares the Church to a fishnet that draws good and bad fish, ultimately separated (Mt 13:47-50), and a marriage banquet, from which one guest was cast outinto the darkness (Mt 22:1-14). This parable ends woth the femous phrase," Many are invited, but few were chosen," which may be interpreted as the distinction between Christians who lack the "wedding garment" of righteous deeds and the actual elect who will be saved in the end. Both are present in the Church, according to Jesus.

A similar state of affairs is seen in the parables of the ten virgins (Mt 25:1-13) and the talents (Mt 25:14-30). In addition, Jesus chose Judas as his disciple, even though the Lord knew the future; and Judas was truly an apostle (Mt 10:1,4: Mk 3:14;Jn 6:70-71; Acts 1:17). Likewise, S.t Paul, in addressing elders (Acts 20:17, 28), states that the Holy Spirit himself has made them bishops; yet from among these very same men, heretics and schismatics would arise (Acts 20:30). He echoes this thought in the parable-like verse in 2 Timothy 2:20.