“Is the doctrine that all doctrine must be found stated explicitly in Scripture found anywhere in Scripture?”
First, that is a silly fallacy.
Scripture says of itself alone that it is God-breathed and inspired. Of itself alone it proclaims it is able to lead one to salvation. It alone is the source of faith, as it claims. It is perfectly adequate and complete to lead believers to maturity, to keep us from sin.
What lesser, uninspired source would you choose? Why would you choose a lower source as the ultimate measure of truth??
Choosing another source is what every pagan does as they spurn truth.
Christians who have read God’s Words and treasured them In their hearts would never accept less than what Be proclaims.
You never answered my question.