My understanding from reading his writings is that he was sincere in his faith; and that his innovations in theology was not around salvation - in that he was orthodox - but around how faith can be also be made to matter in this world and to make a difference in this world. It's a key part of his social gospel and a part of his re-evaluation of values.

This appears to be confirmed by the website of the Baptists who make no mention of innovations, theologically speaking.

Personally, I take it this is how he views Christs parables of the talents. That is not merely to wait for divine assistance - the master of the house - but who must assist himself and others in this world too.

For King, individual salvation in some ways resembles that of historic Protestantism – man is a sinner needing salvation, which is by faith – but differs in other ways, such as in his rejection of a physical resurrection of believers. This understanding fits neatly in his broader understanding of salvation, which applies not just to individuals, but to societies as well.

Individual salvation

Steps of individual salvation

King was uncomfortable with orthodox and neo-orthodox understandings of original sin, but he did accept that men are sinful and that they therefore need salvation:

The first thing necessary for ind. salvation is an honest recognition of one's estranged and sinful condition. One can never be saved until he recognizes the fact that he needs to be saved. ("What Shall We Do to Be Saved?", 1948–54)

King identifies faith, particularly an active faith, as saving:

Faith is fundamentally an act of commitment to that which is believe to be most valuable. Religiously speaking it is total surrender to God. Basically faith is not belief, (although belief is an element in faith) but an act.

For this reason faith is always significant. It is necessary for the very living of life. Even reason itself is a venture of faith. When faith is properly interpreted it is true that salvation is by faith. (Qualifying Examination Answers, Systematic Theology, 1953)

He sees repentance as crucial in bringing about fellowship with God:

Repentance is an essential part of the Christian life. Through repentance man is converted and brought into fellowship with God. ("How Modern Christians Should Think of Man", 1949–50)

For him, the "new birth" is a result of these steps:

Regeneration mean a new life that results after conversion and repentance. It is a new set of values. It is a new adjustment to God, man, and self. It is what Jesus referred to in the Fourth gospel as the new birth. (Qualifying Examination Answers, Systematic Theology, 1953)

Hope of individual salvation

For King, the hope of this individual salvation was not physical resurrection, as taught in the historical church and among the fundamentalists of his day. Indeed, he rejected the idea of a physical return of Christ, a day of judgment, and the physical immortality of believers. Instead, he expected an immortal "spiritual existence" of some kind, and described the future kingdom of God as follows:

Whether it come soon or late, by sudden crisis of through slow development, the kingdom of God will be a society in which all men and women will be controlled by the eternal love of God. When we see social relationships controlled everywhere by the principles which Jesus illustrated in his life—trust, love, mercy, and altruism—then we shall know that the kingdom of God is here. ("The Christian Pertinence of Eschatological Hope", 1949–50)

Collective salvation

With that understanding of the hope of salvation and the kingdom of God, it's easy to see how it connects to a concept of collective or societal salvation. In the sermon "What Shall We Do to Be Saved?", King explicitly stated that "the process of social salvation is the same as the process of individual salvation."

Here's one example of how the two connect. Earlier we saw that King referenced the new birth of John 3 as being "a new set of values" and "a new adjustment to God, man, and self." For him, this lesson was just as applicable to a society as to an individual, as we see in the following excerpt from a speech entitled "Where Do We Go From Here?" (1967):

Jesus looked at him and said, "Nicodemus, you must be born again." [applause]

In other words, "Your whole structure (Yes) must be changed."

[...]

What I'm saying today is that we must go from this convention and say, "America, you must be born again!" [applause] (Oh yes)

^{Note that I've corrected obvious spelling errors in the quoted material.}