I covered some of this before in my previous post, a portion of this bears mentioning again here for purposes of this post, the doctrines of baptisms.
“Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment. And this will we do, if God permit. (Hebrew 6:1-3)