20:23a αφιημι. BDAG, "let, let go, allow, tolerate"; Yeshua gave this authority to his emissaries (apostles) who take the good news to the nations. It is my opinion that this authority was given to the prophets before them. For example consider Elijah's blessing on Namaan the Syrian who asked for permission to help the Assyrian King kneel before his idol. Knowing Namaan's circumstances, Elijah did not forbid it. Such authority is also likely meant for missionaries after the twelve emissaries of Yeshua, particularly in the case where the good news reaches new tribes where the people have a backward culture and cannot be expected to keep all the biblical commands, or where the good news reaches a place of severe persecution just to affirm the name of Yeshua.
The permitting of uncircumcision to the nations, while exiled from Israel is a case of permitting or tolerating, and the forbidding of eating an idol sacrifice is a case of forbidding. As implied however, what is permitted is still a sin, but recognized as a sin of circumstance that is not easily changed. The line is drawn by the missionary with the help of the Spirit in new situations. What is forbidden is forbidden.
The Roman Catholic Church has reinterpreted the meaning of Yeshua's words to mean that their priests are the sole mediators of divine forgiveness which must be obtained through the confessional. The Church takes this text for their own priests to absolve all sins. However, Yeshua was not talking about all sins. He was talking about sins of ignorance or sins of circumstance. And he is not saying the emissaries could forgive the guilt. He is only saying that such sin would not be held against those for whom it is tolerated in respect to ultimate salvation. So the emissaries forgave no sin at all in the sense that the Catholic's claim sin was forgiven. Only the Almighty forgives in view of the proper atoning offering which is now the historical sacrifice of Yeshua on the cross, and not the sacrifice of a graven image, called the host, in the ceremony of the mass. Participation in this was forbidden by the emissaries in Acts 15, because a physical object is being called God, and is being treated and adored as such. The Catechism of the Catholic Church states, par. 1378, 1378 Worship of the Eucharist. In the liturgy of the Mass we express our faith in the real presence of Christ under the species of bread and wine by, among other ways, genuflecting or bowing deeply as a sign of adoration of the Lord. The Catholic Church has always offered and still offers to the sacrament of the Eucharist the cult of adoration, not only during the Mass, but also outside of it, reserving the consecrated hosts with utmost care, exposing them to the solemn veneration of the faithful, and carrying them in procession. As such, the Catholic Church practices Baalism and the sin of Balaam, a sin so serious, that it spiritually blinds those who practice it, and makes them deaf to the Word of the Almighty.