This is a play within the movie The Big, Gay Musical. I would like to recommend the movie to anyone due to its message of acceptance. However, I can't do so because there are several bedroom scenes that I know many of my friends would find over the top, so I will simply summarize enough of the movie to provide context for this video. If you haven't seen the movie yet and don't want any part of it spoiled, you may not want to read the rest of this post, although I wouldn't necessarily call any of it a real spoiler.
The lady singing is the aunt of the young man whose hands she's holding. He's gay and she's a Christian. Earlier in the play, it shows how she sends her nephew to a camp for curing homosexuality and she's sure that Jesus will heal him from his "sickness". The couple in the audience that it shows watching the play are the young man's parents. They're baptist and they just barely found out that their son was gay just before coming to see the musical. It shows them at the beginning of the play being rather uneasy because of the fact that it's about homosexuality, and then you can see that during the course of this song their hearts were touched and at the end of the play they go backstage to congratulate their son.
At any rate, the point is that we all have something to contribute to the world and that it's better to just let other people shine with their own light instead of trying to cast them into a different mold. Let your light so shine before men, that they may see your good works. We all have our own blessings and we should take advantage of them--whether we're gay, straight, bi; whether we're tall or short; whether we're mathematicians or musicians.