In Captain America: The First Avenger, Steve Rogers needed the help of Bucky Barnes when he was attacked in an alley. This was prior to the super soldier serum bonding with his body to create the Marvel hero fans know today. Years later, in Captain America: Civil War, Steve went face to face with Tony Stark in a fight. Not only was his dialogue mirrored as he was beaten down, uttering, "I can do this all day," before Bucky grabbed Tony's leg.
The Captain America: Civil War moment was almost exactly the same as in Captain America: The First Avenger and both cases lead to Steve leaving with Bucky and their enemy being beaten down.
Check out the moments paralleled in the meme below.
This is why I love the MCU. I didn't see the parallels in Bucky grabbing Steve's attacker until just yesterday from r/marvelstudios
At the moment, Captain America is without Bucky Barnes following Avengers: Infinity War. Thanos snapping his fingers in Wakanda resulted in his near-century-long friendship to end (at least, temporarily) with Bucky being erased from existence. The directors of the film, however, don't blame Star-Lord's actions on Titan for Thanos' success.
"I would argue that the fan base could be equally upset with Thor, who chose to throw that ax into Thanos chest and not his head," Joe Russo told ComicBook.com when asked about the unfortunate mistake. "Because he wanted to tell Thanos that he got his revenge."
The God of Thunder hasn't exactly been known for his intelligence throughout his Marvel Cinematic Universe films but, instead, acting on impulse and emotion throughout his tenure in the Marvel Cinematic Universe. His choice to act on his hunger for revenge rather than simply ending the feud and killing Thanos without claiming his revenge through dialogue fits.
"Had he gone for a kill shot, that snap would not have happened. These are choices that characters who are feeling immense pain make and hopefully, the audience can learn to empathize with those characters because they can grow through stories," Joe Russo went on. "Stories can teach us things and that we should try to see every choice from the perspective of the character that made the choice."
Avengers 4 is set to release in theaters on May 3, 2019. It will be preceded by Captain Marvel in March and followed by Spider-Man: Far From Home in July.