The song "Heart" by Jars of Clay is about a deep and unconditional love between two people. The lyrics suggest that the singer has opened up their heart fully to the person they love, offering their heart to them freely and without hesitation. The singer also suggests that there are no obstacles or challenges that can't be overcome with their love. They mention that there are no mountains to climb or papers to sign, implying that there are no external factors that could come between them. The line "I let it get dark, so you'll see the stars" is a metaphor for the idea that sometimes it takes going through hard times to appreciate and recognize the beauty and value of something. In this case, the singer is saying that they allowed the darkness and difficulties to come into their relationship so that their partner could see the true depth of their love and commitment. The song also touches on the idea of giving oneself fully to another person. The lyrics mention the idea of offering one's heart completely, without reservation or holding back. The singer also mentions that they have already given their heart to the person they love, suggesting that their love is unwavering and steadfast. Overall, "Heart" is a beautifully written song that speaks to the depth and power of true love. It conveys a message of commitment, sacrifice, and unconditional love - all of the key ingredients for a long and happy relationship.