Sexuality and Christian faith

Artists like Madonna and Prince have many times drawn comparisons between sexuality and Christian faith (e.g. "Like a Prayer," etc.). Is it blasphemous to make such comparisons?

Blasphemy is an appropriate word to use in the comparison you cited. From what I learned about the lyrics of that song, one line in particular prompted charges of blasphemy. It is my understanding that the music video that accompanied the song clearly contained blasphemous content.

The book of the Bible we know as Song of Songs describes the love between a man and a woman, and symbolizes the love between God and the Christian Church. In Ephesians 5:21-33, the Holy Spirit led the apostle Paul to use the relationship between Jesus and the Christian Church as the pattern of marriage between a man and a woman. When Paul spoke of “love” in that relationship, he used the Greek word “agape.” That love desires the best for another person and is not self-seeking. Another Greek word for love is “eros.” That love seeks to possess and is associated with eroticism. It is significant that Bible writers did not use that word to describe the relationship between Christ and his Church.

Your question illustrates how popular culture, including music, often fails to uphold moral standards. When it comes to entertainment, the Bible’s instruction is always applicable: “Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things” (Philippians 4:8).