I think I understand the point of referring us to Matthew 16:13-18.
If Joseph were legitimate, we would need God to reveal this, like how we know who Jesus is because our Father has revealed this to us.
But . . . I have looked at a little bit of the Book of Mormon and it does not give me what the Bible gives.
So, I am offering to ask . . . what has Joseph Smith said about being personally ruled by God's own peace in our "hearts"?
Jesus did not back down from answering questions, even from enemies. He told them they were wrong, yes, but then He gave good answers which others could benefit from.
And when Paul answered the question about the resurrection, in 1 Corinthians 15, yes he called the person asking "foolish", but then he gave very helpful things about the resurrection, for us all to benefit from.
So . . . what do Mormons officially teach and share about what it is like to be ruled by God's peace in our hearts?
Do you believe that our Father personally rules each of us in our "hearts"?
And what happens because of this? If God is ruling us, is this all the time, and does this mean that He always is leading us, even in every detail . . . as much as we are submissive to how He rules us?
What is needed, so we are being ruled by God's peace in our "hearts"?
Do the Mormons have anything to say about this ? ?
If you don't, this is why I have stayed with the Bible. But I am offering you an invitation to quote what you officially have on this. I am surprised that no one, so far, has found this worthwhile to answer. I have asked this a number of times.