It will not fail because you are. Your 20 inch arms do not serve God in any way shape or form. Your existence, everything you do should be about God. How does 20 inch arms glorify god? Stop trying to interpret the bible to fit your agenda.
I never set out to have really big arms when I trained. I discovered I was blessed physically with big, strong arms. Again, my motivations are pure and God is first in my life. My arms and body (which is nothing special) are always hidden as I mentioned. Some folks are really fast. Some are blessed with artistic talent. I'm physically blessed with strength and ability to grow my arms naturally....it's a blessing not a sin of vanity LOL.
The Power Team from 80s, 90s and 00s are big strong men that used their physical size and strength as a platform to spread the message of Christ....I've seen them live!
I don't have that platform or physical blessing so I speak on Getbig and to my circle of influence in life offline.
My training is again used to remain healthy and strong so that I can serve God and take care of my family.....if I have big arms in the process then bonus blessing by God above!
Sorry you can't see that, but it's the truth.
Do I need 20" arms to spreads the gospel of Christ? LOL, no....but I was blessed with them and still spread his word.