Meaning of "Frozen Heart"
All of the songs in Frozen have some symbolic meaning to them, but "Frozen Heart" definitely has a lot of meanings even just from a few words of the lyrics. Being the opening song, "Frozen Heart" seems to describe Elsa and her powers of ice and snow. But if you think more carefully and listen to it several times, it actually appears to be more of a narration and foreshadowing of the entire story.
The first verse seems to be a description of Elsa's powers: she was born with them, there is beauty in them (being a wonderful sight to little Anna), but also great danger (from the moment she strikes Anna). These are the two sides of this magic, with "the force" being Elsa herself since she has that power. The lines also seem to refer to Elsa as a person: as she grows up, she becomes a beautiful woman and remains a loving sister to Anna (by staying away to protect Anna), but she also sees herself as a force of destruction to Arendelle. Because of this, Elsa shuts Anna out and represses her magic and true personality out of fear. This makes it seem like she becomes a cold and heartless person, or have the said "frozen heart worth mining"...even though she still loves Anna and longs to be with her again.
The second verse seems to be a message to Anna, telling her that she has to reach out to Elsa. She has to take the risk to go after Elsa after she runs away in order to save her sister from herself. By the time she finds Elsa and her palace, Anna finally understands why Elsa had been distant as they grew up. Seeing the beauty of Elsa's magic, but also the danger it can create, makes Anna realize that Elsa shut herself out in order to maintain safety for other people. Even after this truth comes out, Anna still loves Elsa and is probably the only person in Arendelle who does not fear her. Furthermore, to get through to Elsa and have her come home, Anna has to split the metaphorical "ice" that grew in Elsa's "frozen heart" by showing her love. In this case, it is sibling love, and Anna shows just that by sacrificing herself before Hans can kill Elsa. From Anna's act, which thaws (or "breaks") her frozen heart, Elsa is able to realize that love is the key to controlling her powers. With love in mind, Elsa breaks the eternal winter curse over Arendelle. It can be said that love is the key because it is the warmest emotion of all and truly prevails over fear.
As the next couple of verses are short, they can all be combined to represent Elsa and her magic. While "Let it go" is a very obvious reference to her signature song, "Watch your step" refers to the fact that has Elsa literally has to watch her steps by watching every single one of her emotions in order to keep her powers in check. And while her powers make her strong at the right times, even physically, if she lets fear, stress, or unhappiness overcome her too much, she can and will lose complete control of her powers and only unleash strong danger. The biggest examples of this are when she freezes all of Arendelle and strikes Anna in her heart.
The last two verses are almost a word-for-word repeat of those at the beginning at the song, with a couple of changes. "There's beauty and there's danger here" is most likely another reference to the beauty and danger in Elsa's powers. Finally, "Beware the frozen heart" could be represented as a warning about Elsa, as well as a foreshadowing (and danger) to when Anna's heart is struck and frozen by Elsa, but also as the proper closing to the song and introduction to the story.
So while the song seems to be a foreshadowing reference to Elsa and her powers, some of it may also be an allusion to Hans in conjunction with Anna's remark at the end of the film: "The only frozen heart around here is yours." This means that "Beware the frozen heart" also acts as a warning of Hans's true nature. Before this line, the lyrics in the middle of the song can also refer to Hans's character and Elsa's powers simultaneously:
- Beautiful (Hans's handsome appearance) / (Elsa's beautiful appearance, the beauty her powers can create)
- Powerful (Hans's power over Arendelle, his strong ability to deceive/manipulate) / (The strength of Elsa's powers)
- Dangerous (Hans's dangerous power over manipulation, his attempt to kill Elsa) / (The dangers of Elsa's magic, including when she freezes Arendelle and nearly kills Anna twice)
- Cold (Hans's cold and evil nature) / (Elsa's seemingly cold demeanor, the natural coldness of her ice and snow)