It’s a beautiful moment reflecting back on Captain America: The First Avenger, and even more excellent when considered in context with what happens next.
Endgame is particularly tapped into those films, and perhaps the best example is the exchange between Cap and Bucky Barnes a.k.a.
The lines are switched, but “Don’t do anything stupid” followed by the reply, “How can I?
Winter Soldier (Sebastian Stan) right before the former’s final time travel adventure.