And He gave it to us in His word. Jesus told us that His word is truth. And being Holy Spirit breathed, there simply is no other option.
The Catholic church is not consistent in its doctrines. They've changed over time and to get around the obvious, it's been labeled *doctrinal development*. Merely a semantic cover to try convince people that they didn't change their doctrine after all.
Some Protestant denominations (like the Calvinist ones, and the various other "once-saved-always-saved" ones) believe and teach that you cannot lose your salvation after genuinely accepting it, and other Protestant denominations like the Methodists and Seventh Day Adventists believe and teach that you can lose your salvation after genuinely accepting it.
And Catholicism tells us that you both can and can't lose your salvation. You're saved when you're baptized, but not saved after you've been baptized, except that you are.
And you're saved when you take communion, except after you sin, you're not.
But you are if it's a venial sin, you just have to spend uncounted years in torment in purgatory.
It's totally a works based salvation, which Catholics deny it is, saying that it's by grace.
Catholicism isn't even internally consistent.
We love all our Protestant brothers and sisters, but if we find that they are teaching a false teaching, we try to respectfully point that out, just like we try to point out false teachings coming from "Catholics" like Nancy Pelosi and Joe Biden.
Not all. A few.
Perhaps we ought to focus first on what unites us, which to me is Jesus’ gift of salvation to us and forgiveness of all our sins.
Is it any wonder Catholics can’t be sure about salvation?