CLAIM: Jesus said, “I will give you the keys of the kingdom of heaven; and whatever you bind on earth shall have been bound in heaven, and whatever you loose on earth shall have been loosed in heaven” (Mt. 16:19). What did he mean by this?
RESPONSE: This does not refer to the Roman Catholic doctrine of papal decrees. As we have already argued (see “Papal Infallibility”), this passage should not be interpreted to mean that there were (or are) succeeding popes throughout history that have the authority to ratify new doctrines:
First, the NT never states when Peter is given the keys to the kingdom. The future tense of this verse (“I will give you the keys”) means that Peter hadn’t received this authority yet, but it would come in the future. When did Peter receive the keys? This is never once mentioned anywhere throughout the NT.
Second, the verb tense could mean that Peter ratifies whatever God already dictated. The expression “shall have been” is in the future periphrastic perfect tense—an odd and “very rare” tense in Greek. Keener writes, “The verb tenses allow (and according to some scholars even suggest) that they merely ratify the heavenly decree.”
Third, an alternate interpretation is more plausible. Namely, this refers to allowing people into heaven through the gospel. In Luke, Jesus said, “Woe to you lawyers! For you have taken away the key of knowledge; you yourselves did not enter, and you hindered those who were entering” (Lk. 11:52). Moreover, Jesus stated, “Woe to you, scribes and Pharisees, hypocrites, because you shut off the kingdom of heaven from people; for you do not enter in yourselves, nor do you allow those who are entering to go in” (Mt. 23:12). Thus Peter was being given the privilege to spread the gospel to different people groups. This was fulfilled when Peter led 3,000 people to Christ at Pentecost (Acts 2:41). Later, the Holy Spirit waited to descend on the Samaritan believers until Peter arrived there (Acts 8:14-17). Finally, Peter witnessed to Cornelius—the first Gentile convert—in Acts 10. Thus Peter is at the center of God opening up the kingdom to various different groups of people, including Jews, Samaritans, and Gentiles.
We would understand John 20:23 in this same sense. Namely, the apostles were able to bring forgiveness to people through the preaching of the gospel.
 Carson, D.A. The Expositor’s Bible Commentary with the New Internation Version. Vol. 8. Grand Rapids, MI: Zondervan, 1984. 371.
 Keener, Craig. Matthew (Vol. 1). Downers Grove, IL: InterVarsity Press. 1997. Mt. 16:19.