Once saved, always saved... Once a son, always a son... Once in grace, always in grace.
None of these, no, not a single one is to be found in all of Scripture! It is more of a doctrinal cliché that anything else. But I would hope that no one would willfully build the doctrinal foundation of their hopes for heaven upon that which is never stated in Scripture.
The concept of Once Saved Always Saved can be derived from all sorts of arguments from theology, but it cannot be derived from Scripture.
The strange logic of Once Saved Always Saved seems to state that man is free to accept or reject the offer of grace before salvation, but when he gets "saved," he is no longer free to accept or reject this grace. This my friend in utterly illogical. Nothing within Scripture states that we have freedom of the will before salvation, and none afterwards. This is nonsense! John 8:36 states that "If the Son shall make you free, ye shall be free indeed." In this it is implied that a believer in Christ has more freedom than they had before when they were not a Christian. So how can it be said that we are less free after salvation? All because of a Once Saved Always Saved doctrine that no one can find in the Bible?
An example of the absurdity of this doctrine can be demonstrated this way:
A man is walking along the lake, and suddenly he trips and falls headlong into the lake. Now, he cannot swim. He splashes and gasps for air, screaming for help. A bystander notices his dilemma and dives in and pulls the man to safety. He was "saved" from drowning. Now, according to the Once Saved Always Saved concept, this man could never again become careless while walking by a lake and fall in and drown! This is the logic that we are asked to abandon our intellect to.
As for the "Once Saved Always Saved" doctrine, I would feel much better leaving clichés to those in the greeting card industry, and the seriousness of theology and doctrine to those who actually believe the Bible.
For more on the errors of this concept see the following links.
The Eight Pillars of Eternal Security The Eight Pillars of Eternal Security, Part II