KJV: Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them.
NASB: Now I urge you, brethren, keep your eye on those who cause dissensions and hindrances contrary to the teaching which you learned, and turn away from them.
KJV: Know ye not that your bodies are the members of Christ? shall I then take the members of Christ, and makethem the members of an harlot? God forbid.
NASB: Do you not know that your bodies are members of Christ? Shall I then take away the members of Christ and make them members of a prostitute? May it never be!
KJV: But if any man think that he behaveth himself uncomely toward his virgin, if she pass the flower of her age, and need so require, let him do what he will, he sinneth not: let them marry.
NASB: But if any man thinks that he is acting unbecomingly toward his virgin daughter, if she is past her youth, and if it must be so, let him do what he wishes, he does not sin; let her marry.
KJV: Nevertheless he that standeth stedfast in his heart, having no necessity, but hath power over his own will, and hath so decreed in his heart that he will keep his virgin, doeth well.
NASB: But he who stands firm in his heart, being under no constraint, but has authority over his own will, and has decided this in his own heart, to keep his own virgin daughter, he will do well.