I do not admit nor accept the false premise. This "three-legged stool" is a Roman Catholic Church construct that seeks to assert equal authority to tradition and the magesterium as to that of Holy Scripture. They cannot be equal because of the simple truth that only Holy Scripture is the infallible, inerrant, God-breathed and revealed truth. If the supposed traditions or dogmas passed down from church "fathers" and the magesterium go against Holy Scripture, then Scripture has priority. God's truth - as revealed in the Bible - is to be upheld and supported by the Church of Christ, his body, by both its behavior and by its preaching.
In Scripture, the person of God and the Word of God are everywhere interrelated, so much so that whatever is true about the character of God is true about the nature of God's Word. God is true, impeccable, and reliable; therefore, so is His Word. What a person thinks about God's Word, in reality, reflects what a person thinks about God.
-John MacArthur
Basil the Great (ca.329–379)
On the Holy Spirit, 7.16
“We are not content simply because this is the tradition of the Fathers. What is important is that the Fathers followed the meaning of the Scripture.”
This “three-legged stool” is a Roman Catholic Church construct
There is no doubt that protestantism falls on its face without the authority of the Church, just as a two legged stool will stand only as long as no one tries to sit on it.
In protestantism there is no authority and it shows in the fact that one man can find his own interpretation to be the only one acceptable and begin his own brand of Christianity, making the claim that the Holy Spirit has led him to it. Those who agree with him also claim the Holy Spirit has led them to “this truth”.
Before long, we have so called Christian congregations allowing all manner of things that are spelled out clearly in Scripture as sin.
The Church, unfortunately, is not immune to this with Catholics adopting a quasi protestant stance with regard to these things.