It is a pity that was not made clear in the post
## They do not act unfailingly, because their effect can be hindered by the recipient. As to certainty, a Catholic receiving & sacrament & a Protestant praying outside the sacraments are pretty much in the same position. ## Not if your previous statements were accurate. If they can receive grace to become Catholics, it follows that they are not Catholics when they receive that grace. Which means that Christians who are not Catholics can receive grace without being Catholic - which you said was a heresy. Have I misunderstood you ?
Protestants are not in the same position for protestants are refusing graces available through the Catholic Church, even the originators of the reformation --Martin Luther and King Henry recognized that.
Look protestants are saved again and again and again. This which violates many of their own creeds.
Catholics believe in one Baptism for the forgiveness of sin.
Many Protestant denominations are now saying well you really do not need to be Baptized. The reformers are turning in their graves.
What Catholics have is Jesus in the Real Presence and graces from the Holy Spirit through the sacraments that are not available to other Christian Faiths.
The two sacramentals that Protestants have is baptism and matrimony as these would be recognized as the bible states for a Priest or Bishop is not necessary. The truth of the matter is Protestants are even destroying the Sanctity of these with divorce for compatiability and remarriage which is definitely a no no right out of the bible and protestants know it. Baptism well many are doing away with that as unnecessary esspecially the new mega Churches.
Now Matrimony would be valid between a Protestant and Protestant. Between a Protestant and Catholic unless special permission is granted the marriage may not be valid as the Catholic having the fullness of the faith is going outside the faith for a sacramental. For this ask a priest.
The Sacraments missing is Communion, Confession, Confirmation, Holy Orders, and Annoiting of the sick.
The reformers understood the Sacramentals but many years later the Protestant Churches abandoned them or recognized they were not valid due to not having Apostolic Succession.
Plus while protestants have the bible as the Catholic Church. The bible is not infalliblie as it is a book. Protestants are missing Sacred Traditions and Sacred Teachings.
Plus they are missing the teachings of the early Church Fathers.
Protestants are not One Church under Christ and thus are not one in Christ for the early Church Fathers recognized the authority of the Church and the Real Presence (Transubstansiation)
Protestants are breaking apart and many of them are on the brink of collapse.This can be shown by the many different denominations. Even a Baptist Church down the road from eachother will have different teachings. The same goes for the Lutherans, Anglicans, Methodists, etc…
If at the time the church A Protestant goes to does not meet with their lifestyle than Protestants will change their church.
Now what the Catholic Church says is that the Church is not the Judge and that Jesus is. However the Catholic Church being one Church is the way to salvation. This can be shown by attending a Catholic Church in Rome to Australia to Africa to the U.S… It does not change, and has not for over 2000 years and has grown by leaps and bounds every year. While the Protestants denominations are shrinking in size. as a Catholic it is the same no matter where you go. May be some cultural differences but I can follow along never missing a beat even in a different language. Our Boss has the final say.