What conditions does he put on "by which also you are saved"?
The NKJV does a better job of the Greek word used there for memory.
katechó: to hold fast, hold back
Original Word: κατέχω
Part of Speech: Verb
Transliteration: katechó
Phonetic Spelling: (kat-ekh'-o)
Short Definition: I hold fast, bind, restrain
Definition: (a) I hold fast, bind, arrest, (b) I take possession of, lay hold of, (c) I hold back, detain, restrain, (d) I hold a ship, keep its head.
1 Cor. 15:2 by which also you are saved, if you hold fast that word which I preached to you—unless you believed in vain
If they don't hold it fast it was for nothing.
And there we have the DIY version.
Thank you for your input.