After six years, WandaVision finally showed exactly why Vision was worthy of lifting Thor's hammer. The original moment indicating Vision's worthiness came all the way back in 2015's Avengers: Age of Ultron. As the Avengers bickered with one another, Vision sprang into action, casually picking up Mjolnir and handing it to Thor. As a newborn synthezoid, Vision had no understanding of the significance of the act, but the other Avengers certainly did, and Vision picking up the hammer was all the proof they needed to trust him.
Mjolnir has a long and storied history in the comics and the MCU alike, and though its history is vast, the one aspect of it most people are familiar with is the fact that only the «worthy» can lift it. As its inscription says, "Whosoever holds this hammer, be he worthy, shall possess the power of Thor." In the comics, Thor's hammer has been lifted by various characters over the years, leading some to question how the hammer determines worth. Some have speculated it's Odin's personal determination, while others have posited an interesting theory that the wielders themselves decide whether or not they're worthy. However, in both the comics and the MCU, it's usually able to be possessed in a moment in which the character is at their most noble, their most stalwart, and their most selfless.
Related: The MCU Has Forgotten Mjolnir's Other Great Power
Those qualities culminate in Vision's actions in WandaVision episode 6, «All-New Halloween Spooktacular!» in a scene that pays off Mjolnir's faith in Vision all those years ago. Vision discovers Scarlet Witch's magic hex barrier around Westview, and forces himself to break through it at the expense of his own well-being as his body starts to deteriorate once
Read more on screenrant.com