How do we know that the gates of hell have not prevailed?
Just because the Church has a following does not mean the gates have not prevailed. Several other Churches that are in error have not gone away and to them, the gates of hell have not prevailed either.
So how do we know?
We know because the historical facts testify to it. The Church still teaches the same doctrines it did in the first century: the Eucharist, the necessity of confession, the reality of purgatory, all the way down to the Church’s moral teaching on things like contraception; all of these things have been a part of the Catholic Church’s teaching since the very beginning.
In regards to the other churches, they are clearly not the Church established by Christ: Christ only established one Church and that Church is clearly (when one reads the history) the Catholic Church. The “gates of hell” have, in a sense, prevailed over those other churches (no offense meant to our Protestant brethren in saying so), in the sense that they have lost some of the moral truths that the Church teaches and thus have become accepting of certain things which are mortally sinful, and thus put souls in jeopardy. The prime example is the case of contraception, which has been condemned by the Catholic Church since the first century, a stance which was followed by virtually every branch of Christianity until the 1930s when the Anglican Church first accepted its use; every other Protestant sect shortly followed suit. Contraception is a mortal sin, and all mortal sins are “gates to hell,” in a sense. In that first storm of the sexual revolution, only the Catholic Church withstood this assault on truth.
Equally important is the uniquely Catholic doctrine of transubstantiation; the true presence of Christ in the Eucharist. The Eucharist is vital to the spiritual life. As Jesus said, “If you do not eat my flesh and drink my blood, you have no life within you.”
Again, none of this is said to slight our Protestant friends or suggest that they do not have a real relationship with Our Lord, but it does no one any favors to sugarcoat our understanding of the truth. The Catholic Church is the Church Christ established and it is the only Church that has preserved the fullness of the truth He taught.
Islam and Hinduism have huge followings and they are not joined to our Church at all. To them, the gates of hell have not prevailed either.
Islam and Hinduism are not monolithic organizations. There are countless forms of “Hinduism”, with no definitive set of teachings or doctrines. Islam is more organized, but there is still no central Islamic authority.
Or is Christs promise in regards to guarding the Church from heresy? However, I still cant see how Christ has promised to keep the Church pure in understanding faith and morals infallibly when from the very beginning it almost seemed like morality was non existent.
Yes, it is in regards to both heresy and dissolution.
Morality has never been non-existent. Morality is a system of timeless truths, all of which the Catholic Church has taught from the beginning of its existence. The failure of its members to practice these teachings does nothing to take away from the fact that the Church has always taught them.