HMMMmmm... let's see now...
Well; there are Seven Sacrements...
Well do you have an answer?
I would like to know.
You indicated you would answer if one “cared”
The question posed to you:
**What is in “sacred tradition” that is not in the Word that is essential for having eternal life?”**
TIA
HMMMmmm... let's see now...
Well; there are Seven Sacrements...
The two are not totally separate from one another, so it's a false understanding to begin with to view them as such. Sacred Tradition contains, in essence, the oral teachings of the Apostles as they have been handed down, as well as the proper understanding of Scripture.
The Church existed not only before the Canon of the NT, but before the NT itself. So on what basis did the fathers determine which books belonged in the Canon? They measured each one against Sacred Tradition.
Not only was Sacred Tradition the basis by which the true Scripture was determined, but it is the basis by which Scripture is interpreted. ST provides the context necessary to understand Scripture as God intended. So to ask, "What's in ST that's not in Scripture," is like asking, "What's in cake that's not in the ingredients." Scripture is itself a part of Sacred Tradition, in the sense that it can only be understood and interpreted in the light of Sacred Tradition. Together, they form the Deposit of Faith. I can't recall who said it, but there is a quote that says (paraphrasing) "Sacred Tradition is the lens which focuses the Light of God on Scripture to reveal the truth contained therein." This is how a truth such as the Immaculate Conception (Her utter sinlessness was discussed and believed by the fathers, and not simply invented in the 1800's as some purport, but I digress) is brought to light, by the Grace of God.
That's the cliff notes version.