What all Christian denominations believe once saved always saved? I know the Baptists believe this what are some of the other groups? Thanks.
“Once Saved Always Saved” started out in the Reformation as the doctrine of the “Perseverance of the Saints.” This was taught by the early “Reformed” theologians such as Bucer and Calvin (not, however, by Luther or the Lutheran tradition). The doctrine of “Perseverance” means that if someone once receives regenerating grace, they will persevere till the end. Another way of putting it is that the gift of regeneration and the gift of final perseverance are always given to the same people–in contrast to the traditional Augustinian position that many who are regenerate do not receive the gift of final perseverance.
One of the main consequences of this view is that regeneration can’t be identified with baptism, since it’s possible for baptized people not to persevere. So the Reformed tradition denies baptismal regeneration.
The major “Reformed” denominations, besides the obvious ones with Reformed in their title (Christian Reformed, Reformed Church in America, etc., just to name some of the U.S. ones), are the various Presbyterian groups and the Congregationalists (most Congregationalists in the U.S. are part of the United Church of Christ, though these are very liberal and probably don’t worry much about perseverance for the most part). Anglicans have some relationship to the Reformed tradition, though the perseverance of the saints has never been an Anglican doctrine (some do believe it).
The Baptists are also an offshoot of the Reformed on the other side (i.e., the Anglicans are more Catholic than mainstream Reformed; the Baptists are less). Some Baptists consider themselves Reformed (i.e., they believe in unconditional predestination), and their doctrine of perseverance is like that of conservative Presbyterians.
Most Baptists today, however, hold an “Arminian” view of predestination (God freely offers grace to all and the fact that some accept and others reject it does not result from God’s sovereign choice but from human free will). But at the same time, the majority of Baptists in the U.S. (Baptists in Europe are quite different) still hold on to the doctrine of “eternal security.” That is, while the traditional Reformed believe that God elects certain people and gives them the gifts of regeneration and perseverance, the typical U.S. Baptist believes that human beings can choose freely to believe in Christ, with the result that such a person will be saved for all eternity. The problem with this is that without a doctrine of predestination, you’re left with the possibility that a “saved” person might choose not to lead a holy life. Many non-predestinarian Baptists do hold on to a doctrine of perseverance, teaching that a truly regenerate person will want to lead a holy life. But without a robust doctrine of predestination, this is often a rather fragile and confused teaching.
This is the doctrine of “OSAS” that you no doubt have in mind. The Baptists are the only major denominational group who teach it (and as I said Baptists outside the U.S. are not nearly as fond of it–it’s largely an American teaching). However, many “non-denominational” churches and small denominations have essentially Baptist beliefs (as others have pointed out on this board). And the doctrine is so popular in the U.S. (especially in the South) that many members of denominations such as the Methodists (who do not historically believe any such thing) hold to OSAS.
I hope this is somewhat helpful. Basically the common Baptist view takes the “nice” part of Calvinism (once you put your faith in Christ you are secure for all eternity) and leaves out all the tough stuff (you can’t freely choose to accept Christ unless you are sovereignly moved by the grace of God). I try to respect everyone’s views, but this one is hard for me to respect, because it seems such a cop-out. I don’t agree with thorough-going Calvinism, but I can respect it.
In Christ,
Edwin
Outstanding, thank you! 
my sister-in-law belongs to free will baptists and says they do not believe in once saved always saved.
Since their are different Baptist denominations it would be impossible to say what the every BAPTIST beleives and this further proves the weakness of protestants are they don’t even agree among each other when they are under the same denominational theology you will have Presbyterians diagreeing with Presbyterians and Baptist disagreeing with other Baptist on essential issues such as soteriology.
Many Baptise have a Calvinistic bent to them so many would agree with once saved always saved but since they are protestants many will disageee with their Baptist brothers on this issue.
Pentecostals and Charismatics, as groups, seldom believe in OSAS.
The Methodist tradition, including its very many offshoots, rejects it, although some individuals will be found in those denominations who do accept it.
From the beginnings of the Baptists during the Reformation era, they’ve been divided between General Baptists (who reject Calvinism) and Particular Baptists (who accept Calvinism). The Southern Baptist Convention churches overwhelmingly accept OSAS; and since they’re the biggest, it makes it look like a “Baptist” doctrine. Someone like me, who has moved intimately in these circles for decades, can give you the inside scoop that plenty of people in the pews have their doubts about OSAS, even though “their church” teaches it.
Practically all Black churches of every denomination reject OSAS. I know of none who accept it, though I’m open for correction on that.
Bottom line: many, perhaps most, “born-agains” do not believe in OSAS. They believe in faith alone, but it is a faith that must continue, rather than a one shot, paid-up, non-forfeitable act of faith.