In "Sonnet 30", by Edmund Spenser, the poet uses a metaphor to explain his situation: he compares the unloving heart of Elizabeth with ice, and his own loving heart with fire. He then wonders why, if her heart is ice and his fire, he cannot melt it and make her love him. Instead, he appears to push her away even harder with his love, fortifying the ice instead of melting it, but that makes him love her even more. Therefore, he wonders "What more miraculous thing may be told that fire, which all things melts, should harden ice: and ice, which is congealed with senseless cold, should kindle fire by wonderful device?"
The poet's message is that, even when you have everything to offer, sometimes love is unattainable.