What's necessary

No one would require that one even understand, let alone believe in, salvation by grace through faith in order to be saved by grace through faith. In the matter of personal salvation, "by grace through faith" is the "how"; being saved by grace and receiving the gift of faith is the thing itself. Of course, the truth of the doctrine of salvation by grace through faith is taught is Scripture (Eph. 2:8-9 in particular) and is the subject of many catechetical statements and theological works: it is part of coming to know God. Protestants will mostly affirm it as an essential doctrine, at least in the sense that, if one actively believes the converse, one's Christianity is suspect. On the other hand, if one is a new Christian, the lack of any fixed belief in the doctrine of salvation by grace through faith is a sign only of the need to study further the acts of God in the Bible, not of any defect in one's salvation.

    If this can truly be said of so mighty and nearly universal a doctrine as salvation by grace through faith, namely, that it is not essential for salvation, what should we say of lesser doctrines, say, for instance, the theory of the Atonement?