Even as Paul addessed this church,as an Apostle he was being guided into all truth, by The Spirit of God. In chapter 3 he explains in part what "must" take place in the church;

14These things write I unto thee, hoping to come unto thee shortly:

15But if I tarry long, that thou mayest know how thou oughtest to behave thyself in the house of God, which is the church of the living God, the pillar and ground of the truth.

The word oughtest is the word must. Like you must be born again. Or Jesus saying I must go to Jerusalem. It was not cultural,it is still binding today.

Paul would sometimes differentiate when He repeated a teaching he heard directly from Jesus, or when He was speaking on His authority as an apostle.like here in 1 cor 7;

10And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband.

If it is written in scripture,it comes from men as they were borne along,or moved by God,
19We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts:

20Knowing this first, that no prophecy of the scripture is of any private interpretation.

21For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.

__________________
Anthony D'Arienzo
Sunday School Teacher
Hope Reformed Baptist Church:
Medford, N.Y.