Updated: May 16, 2020
In our first reading (Acts 15:1-6) today, we hear of the beginnings of what some have called the first council of the Church, which happened in Jerusalem, long before the First Council of Nicaea in 325 A.D.
The matter at hand was the issue of circumcision. Some believed that in order to be Christian, one had to also live out the tenets of the Jewish religion, which included circumcision. At the time, the matter wasn't so clear. It took a gathering of the apostles and presbyters to discern together how God's unchangeable revelation to them in Jesus applied to that particular issue.
The very fact that it took a gathering of these leaders to understand the truth of what God had revealed to them through Jesus (it wasn't a gathering to "vote" on what the resolution would be) highlights a certain reality: no one is an island unto himself (or herself) with regard to the truth.
We share in the truth that we have received from Jesus, who is the Way, the Truth, and the Life. No one is infallible on his/her own except for Jesus Christ (the pope does speak infallibly, however, not when expressing personal opinion, but rather when speaking under very specific circumstances, giving voice to the community of the Church, in union with Apostolic Tradition and Sacred Scripture; when invoking infallibility, the Pope even speaks in the plural: "We declare, pronounce and define the doctrine...").
Leading into this biblical account of what some have called the Council of Jerusalem, even Saint Peter himself had been in the wrong initially with regard to the necessity to live as Jews before becoming Christian. Saint Paul famously corrected him on this account, as he describes in Galatians 2:11-21.
Again, the community of faith is the context in which truth in its fullness can be pondered and articulated. But it must be a community united to Jesus Christ. This is the organism we call the Church. In our gospel passage today (John 15:1-8), Jesus says: "I am the vine, you are the branches." Only in Jesus Christ do we have access to the truth. A branch is dead on its own. It must be one with the vine in order to survive and bear fruit. Likewise, the truth dies within us if we were to be separated from Christ.