Therefore we also pray always for you that our God would count you worthy of this calling, and fulfill all the good pleasure of His goodness and the work of faith with power, (12) that the name of our Lord Jesus Christ may be glorified in you, and you in Him, according to the grace of our God and the Lord Jesus Christ.  (2:1) Now, brethren, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we ask you, (2) not to be soon shaken in mind or troubled, either by spirit or by word or by letter, as if from us, as though the day of  Christ had come.

The apostle Paul wrote this second letter to the Thessalonians.  His first letter to them addressed the second coming of Christ and might have resulted in some of the faithful to indulge in curiosity as to His coming. (Nothing has changed and people are still trying to figure out when this world will end.). This was a matter of great consequence in those ancient days as some might despair of Christ returning or feel like they missed it – or grow impatient and fall away so that the sure hope of the resurrection might be undermined. Paul urges his readers not to be too credulous and swallow the pretext that “that day” is at hand.

Paul warns the Thessalonians not to be shaken in judgment – that good judgment means faith that rests on sound doctrine. He warns them against the spirit of men speaking  words of pretended prophecy; the pious in that day apparently spoke that way to give themselves stature. They are also being warned about spurious letters/epistles using Paul’s name so as to impute false doctrine to him.  It is the Spirit of God, not man that has any authority.

As to the day of Christ being at hand; think of it as at hand with regard to God. And to God, one day is as a thousand years.  We know that Christ Jesus will return but we know not the day or hour. The Lord wants us to constantly watch.