Still the same old works-salvation moralism, eh? You're like a dog with a bone with this stuff!
1 Corinthians puts the brakes on your thinking BCSenior. Read chapters 3, 5, 6 and 11. The Corinthian believers were messing up big time, engaged in some very gross and willful sin, and yet, Paul confirms again and again in his first epistle to them that they were, nonetheless, fellow brothers and sisters in Christ. In the same chapters where he criticizes them for their sin, Paul calls them "babes in Christ," God's "building" and "field," "brethren," "temple of God" and "saints." Clearly, Paul did not think that sin in a believer's life ejected them from God's family and kingdom. He certainly emphasized how incongruous with their identity in Christ sin was, but he never once says, "If you sin, you're out."
Typically, saved-and-lost moralists conflate inevitability with necessity. They assume that because good works are inevitable to a spiritually-healthy and mature believer, that, therefore, good works are necessary to being a believer. This is like thinking that an apple tree must bear apples in order to be an apple tree. But what about the apple tree too immature to do so? Or the apple tree set in bad soil, without sufficient nutrients in the ground to nourish it and enable it to produce apples? Or the apple tree infected with disease or insects that prevent it from bringing forth apples? It would be silly to say of these sorts of apple trees, "Oh, those aren't apple trees. They must produce fruit if they are to truly be apple trees. It is necessary to being an apple tree that apples be produced." But this is what folks like BCSenior (and others on this thread) are saying about Christians. They don't allow for spiritual immaturity, or for a lack of proper spiritual nourishment in the teaching a believer has received, or the hindering effects of "spiritual disease" like addictions, deeply-ingrained sinful habits, and unrecognized lies shaping their living.
To further delineate the difference between inevitability and necessity simply imagine a boat with a hole in its hull lying on the bottom of a lake. A scuba diver finds it and says to himself, "Oh, look, a boat!" He recognizes that the boat is a boat even though it's not floating, as it was made to do. Inevitably, if the boat had no hole in it, it would be on top of the water, floating. But, is the boat not a boat because it's not floating? Is floating necessary for the boat to be a boat? What if the boat was in dry-dock getting painted? It wouldn't be floating, as it was made to do. Is it therefore not a boat? Of course not. While floating is inevitable for a boat in good repair that has been put on the water, it's not necessary to a boat being a boat; the boat doesn't have to float in order to be a boat.
So, too, with a born-again believer. While good works are inevitable to a healthy spiritual life in Christ, they aren't necessary. As some have already pointed out in this thread, a Christian doesn't have to be righteous in order to be a Christian; a Christian is righteous because s/he is a (spiritually healthy and mature) Christian.
The moralist typically objects to this thinking, resorting to ridiculous extremes in their objection. "You're saying a born-again Christian can live like the devil, then!" No, all I'm saying is that sin will still plague a believer, born-again though s/he may be - especially early on in their walk with God. Over time, as the believer matures, sin becomes increasingly the exception in his/her life, their position in Christ reflected more and more in their daily condition (living).
Righteousness is not an end in itself, as the moralist typically contends, but merely the means to joyful fellowship with God. It leads the immature believer badly astray to obscure communion with God with do's and don'ts, scaring them into obedience to God with threats of lost salvation, rather than pointing them to His love as the basis for their walk with Him. (See 1 John 4:16-19; 1 Corinthians 13:1-3; Romans 8:38-39) Scare tactics appeal to Self-interest, to self-preservation, not to love for God. Anything that produces this focus counters rather than assists Christian living. Truly enjoying God, walking well with Him, requires death to Self, not a fearful striving to protect Self. (Matthew 10:37-39; Matthew 16:24-25; John 12:24-25)