20 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:I Corinthians 10:12
21 For if God spared not the natural branches, take heed lest he also spare not thee.
22 Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off. And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again.
Wherefore let him that thinketh he standeth take heed lest he fall.Romans 11:20-23
1 Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it. . . .Romans 11:20-23
11 Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.
12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.Philippians 2:12-15
13 But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.
14 For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end.
12 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.And finally, a timely warning in our lust-filled society on the need for self-control over the body, lest Christians should become castaways relative to God's kingdom:
13 For it is God which worketh in you both to will and to do of his good pleasure.
14 Do all things without murmurings and disputings:
15 That ye may be blameless and harmless, the sons of God, without rebuke, in the midst of a crooked and perverse nation, among whom ye shine as lights in the world;
I Corinthians 9:24-27
24 Know ye not that they which run in a race run all, but one receiveth the prize? So run, that ye may obtain.
25 And every man that striveth for the mastery is temperate in all things. Now they do it to obtain a corruptible crown; but we an incorruptible.
26 I therefore so run, not as uncertainly; so fight I, not as one that beateth the air:
27 But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.