The "Riddle of Steel" is a concept from the 1982 movie Conan the Barbarian, directed by John Milius and starring Arnold Schwarzenegger as Conan. The riddle is a philosophical question about the nature of strength, power, and what truly gives a person the ability to control their destiny.

In the movie, Conan's father tells him that the secret of steel is what gives men their strength and power, and that they must trust in steel (i.e., their weapons). This belief is central to Conan’s understanding of the world, where strength and the ability to wield a sword (steel) are of utmost importance.

Later in the movie, the villain Thulsa Doom (played by James Earl Jones) challenges this belief by saying that steel is not the ultimate power; instead, it is the will, or the strength of the flesh, that is more powerful. He demonstrates this by having one of his followers leap to her death simply because he commands it, showing that his influence over people is stronger than the power of a weapon.

Conan: The riddle...of steel.
Thulsa Doom: Yes! You know what it is, don't you boy? Shall I tell you? It's the least I can do. Steel isn't strong, boy, flesh is stronger! Look around you. There, on the rocks; that beautiful girl. Come to me, my child...

(Girl jumps to her death.)

Thulsa Doom: That is strength, boy! That is power! What is steel compared to the hand that wields it? Look at the strength in your body, the desire in your heart; I gave you this! Such a waste. Contemplate this on the Tree of Woe. (To his henchmen) Crucify him!

Thulsa Doom’s perspective suggests that the power of the human will, and the ability to control others, is stronger than the physical power provided by steel (weapons). It raises the question of whether true power lies in the material (steel) or in the immaterial (the human will, belief, or influence).

The riddle also implies that steel itself is not inherently powerful; it is the person wielding it who gives it strength. Without a strong will or purpose behind it, steel is just a tool. Throughout the film, Conan grapples with this concept, trying to understand what truly makes him strong. By the end of the movie, he realizes that while steel (his sword) is important, his true strength comes from within—his resolve, his experiences, and his will to survive and achieve his goals.

The Riddle of Steel asks the question, what is strongest that one could take to oneself?

In the movie, Conan's father believed it was Steel, but Steel failed him and he died (savaged by dogs).

Thulsa Doom, for a time, believed steel was strong ("more valuable than gold or jewels") and he pursued it thinking that it would make him so. Over time he came to favor Flesh (as shown in the quote above), but Flesh ultimately failed him and he died (decapitated).

Both Flesh and Steel are nothing without conviction. The answer to the Riddle of Steel is Will.

This point is made below in a slightly different context:

"AR-15 or you are gay. Pistols are for suicides and executions and gays."

You and every person that replied to you are 100% part of the problem. You are circle-jerking arguing about weapon type and even caliber.

You know what beats the Sig, Glock, and AR-15 platform all day every day and twice on Tuesday?

A .25 caliber Saturday Night Special in the hands of a gangbanger willing to use it at a moment's notice. While you are dying slowly from a gut wound at point blank range your last thought will probably be, "but that is a mouse gun!"

The best firearm is the one that you are willing to use.