Apostle Paul and the holy spirit would disagree with that statementEverything we can REQUIRE of a follower of Jesus is contained in Acts 15
Acts 20:25-31 KJV — And now, behold, I know that ye all, among whom I have gone preaching the kingdom of God, shall see my face no more. Wherefore I take you to record this day, that I am pure from the blood of all men. For I have not shunned to declare unto you all the counsel of God. Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood. For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock. Also of your own selves shall men arise, speaking perverse things, to draw away disciples after them. Therefore watch, and remember, that by the space of three years I ceased not to warn every one night and day with tears.
Philippians 2:12-13 KJV — 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. For it is God which worketh in you both to will and to do of his good pleasure.
work out = katergázomai, kat-er-gad'-zom-ahee; to work fully, i.e. accomplish; by implication, to finish, fashion:—cause, to (deed), perform, work (out).
So in context it should read WORK FULLY YOUR SALVATION/ OR WORK TO COMPLETION YOUR SALVATION
based on the obedience to what they had been taught.
It doesn't take three years to relay 4 things which had already been communicated in a letter. There are obviously more things to obey according to the written records we have from the Apostles.
To say otherwise is a huge error. Your statement does not hold water.