All the songs are about crying because faithfulness or fidelity is lost. What does religion ensure? It ensures fidelity, faithfulness and patience.
Love provides beauty in every aspect. For instance, if a song is sung with love, if it is played with love, it gives an insatiable pleasure. I mean when you do something with love, it yields perfect results. If one talks with love, it can be listened to with an amazing joy. If one looks at another with love, it gives an amazing joy. Even when you show love to a flower, that flower becomes so beautiful and so sweet.
There will be the best of music in the Heaven. The music in the Heaven, the songs there, will enrapture people.
The Prophet David (pbuh) was singing with love for Allah and dancing. At that period because he danced, there appeared some people who looked down at him in their own twisted minds.
The bigots of the time criticized the Prophet David (pbuh) because he sang and danced. Actually he was dancing out of love of Allah, how beautiful this is. Furthermore the Prophet David (pbuh) has a very beautiful voice.