American Standard Version (ASV):
to the end that ye be not quickly shaken from your mind, nor yet be troubled, either by spirit, or by word, or by epistle as from us, as that the day of the Lord is just at hand;
King James Version (KJV):
That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.