We need more assurance than this. When dealing with the truth that leads to eternal life (ponder "eternal life" for a second), we need a clear, non-conflicting source of it. This is why God established his Magisterium. The Magisterium is the teaching office of the Church which has the divine authority to definitively interpret God's revelation to man. The Apostles, with Peter as their head, were the first to occupy this office. Today, this office is occupied by the current pope (the successor of Peter and Bishop of Rome) along with the bishops in communion with him.
Many people may have a problem with this. We want to be able to interpret God as we see fit for our own situations in life. We don't want to see the Pope, or any bishop, as having authority on this truth. The error in this objection is that it makes truth relative. Take a moment right now and do a Wikipedia search on "List of Christian Denominations." Be sure to scroll all the way to the bottom. Is this what God intended? Pluralism of Christian truth?
Since we in the 21st century were not eye-witnesses to the definitive revelation of God (Jesus), we must rely on others to learn of this revelation. Think about it- God is not going to give his beloved children a full revelation of himself only for it to be soon lost leaving everyone to question and argue over it. To prevent division, God established his true Church on St. Peter, our first Pope.
"And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.” (Mt 16:18-19)Christ established a living authority to guide his followers until the end of the ages. Thank God for this authority! Without it we must constantly struggle to stay afloat in a sea of relativism where truth in its fullness can never be found. We remain prisoners to what Pope Emeritus Benedict calls "The dictatorship of relativism."
"..relativism, that is, letting oneself be "tossed here and there, carried about by every wind of doctrine", seems the only attitude that can cope with modern times. We are building a dictatorship of relativism that does not recognize anything as definitive and whose ultimate goal consists solely of one's own ego and desires." (Pope Benedict XVI)It is the Church's authority that prevents this "relativism" from taking hold on us. God does not want us to be "tossed here and there, carried about by every wind of doctrine." He wants us to know the truth. Relativism is so dangerous because it steals this truth from us. We then run the risk of remaining dead in our sin, and ultimately having to face our demise.
Infallibility
It's important to know that the Pope (or any bishop) is not God, and should not receive any "worship" on our behalf. These are regular men with flaws just like anyone else. Some popes can even be considered evil, and may likely be spending their eternity in Hell. So how does that reconcile with the doctrine of papal infallibility? How can one have the capability of being imperfect as a person and at the same time teach faith and morals perfectly? That's a big question that one could research for a lifetime.. Again, my final conclusion is this: God Loves Us. It's that simple. How can our loving Father in heaven leave us to be lost sheep without a shepherd? Here's Fr. Barron's take on this matter:
So what does our Church, shepherded by her Magisterium, teach us?
She teaches us everything we need to know for our salvation (Compendium #162). We need to listen to her carefully as she preserves our unity with God and with one another.
Where can I find the essentials of what our Church teaches?
The essentials can be found in the Catechism of the Catholic Church. Along with the Bible, the Catechism should be read and reflected upon regularly.
