One of you has asked me, "If many are called, but few are chosen, then how do I know I'm saved?" Eternal insecurity is a scary thought, and the short answer is this: If you are worried about it, you're probably ok. Since the short answer still leaves room for wiggle, (which is not very secure), I'll give a long response as well.
The passage referred to is from Matthew, 22. It's a pretty haunting parable that many people probably are not aware of. Basically, a king hosts a wedding party and invites a whole bunch of people who it explicitly says do not deserve to be there. During the banquet, the king notices a man among the crowd who is dressed in rags and says to him, why aren't you in wedding clothes? He tells the guards to tie him up and throw him out, then he says, "Many are invited, but few are chosen." It seems pretty harsh upon first glance until you interpret it in light of the whole of scripture.
Elsewhere, we see that we are not merely guests at the wedding, but we are the bride. We are an unworthy bride, but He cleanses us by His blood and baptism and clothes us with his own righteousness. Remembering this, imagine that at the door of the Kingdom that day, the filthy beggar was offered a bath and some clean clothes to wear inside to honor the King, but the beggar refused, stating that he was good enough for the court without it. He was then rejected not because he had no righteousness of his own, but because he rejected the righteousness offered to him.
We are chosen when we are found worthy, just as you choose the cupcake with the most icing on it. This happens after we accept His provision for us. Yahweh does not choose arbitrarily, that is a fact of his character. (Allah is the finicky one). He must therefore choose based on merit. Since we have none, the merit is extrinsic, namely, acceptance of the provision of God. The whole of scripture testifies to the fact that men are found righteous always only when they accept the provision of God.
In our culture, we have two big hurdles to overcome in seeing the truth of this passage:
1.) We hear "Many are called, few are chosen," and we think "Many will enter, few will win." They are similar, but there are some fundamental differences that keep salvation from being a cosmic sweepstakes. First, in the parable, the invitation is opened by the King, whereas in the lottery, the beggar pays for the opportunity. Salvation is initiated by God, not by the sinner. Second, "few will win" suggests that favor will be shown by luck of the draw. "Few are chosen" goes a bit deeper than that. It suggests that there is some sort of fixed standard by which one can be favored. This standard is righteousness. In the sweepstakes, one is forced to guess what the winning numbers are, whereas in the salvation, one is allowed to ask the benefactor the right numbers and input them. One is a gamble, and the other is a sure bet. Eternally speaking, betting against the house cannot win.
2.) We sympathize with the beggar and his desire to "be accepted for who he is." After all, he can't help it, and it's probably the King's tyranny that keeps him from being able to buy good clothes in the first place. There is a romantic modern concept that suggest that people are products of their nature and nurture, and that they simply cannot help the way they are, and if you can't love them without expecting their effort to change, then you are simply a cruel, intolerant monster. That means old King should have looked at the beggar and said, "I'm no better than you, let's just all get along. I'm sorry my feudal system has been rough on you." But we forget that parables are analogies. The beggar isn't just a beggar: he is a willful sinner. And the clothes aren't just clothes: they are righteousness. In that case, the King IS by DEFINITION better than the beggar, and has every right to reject the beggar who has no desire to be clothed in a manner that honors the atmosphere of the occasion, especially when he had ample opportunity to do so. The reality is, the beggar was too proud to accept the charity of the King, and therefore did not belong in the presence of the King.
This is why I say if you're concerned about it, you're probably ok. The "probably" is not a mater of chance. It's a matter of your willingness to accept the invitation of grace in the form of clothing yourself with Christ's righteousness and thereby being worthy to be chosen to share in His eternal riches as not just a guest, but as joint-heir to the Kingdom. That's a very secure eternal position.