Well this is is an interesting topic and like almost everyone said, it depends of the content and if it worships God. Actually, if we look at it in an objective way, every song that doesn't worship God is like..... pointless; but don't misunderstand me, I'm not sayin it's evil either(again depending of the content). I can't make a good example cause I'm not actually saved but I have a good and close friend who is saved. Before she was saved she was like a depressed person, and liked to listen punk music and you know...that commercial music that we probably hear everyday. Well, i know her since we were 12, and since a few years ago she's totally changed. I saw how she didn't' even feel interested in commercial music anymore, not saying that is evil, just....pointless, I mean she can enjoy some of that music a time or another, but is like she doesn't enjoy it like before, so when you're in her car you just hear christian cd's( classic,pop,punk,pop/rock,blues and one day I even heard banda lol) .
I'm mentioning that cause It shocked me how she changed in the music subject and probably I can't totally understand it, cause I'm not where she is, but the thing is...I think that when you feel so close to the Holy Spirit , He automatically tells you what is good to hear...or even just take away those interests you have and replace them with the ones that are good for you and for Him, so you automatically know if you're doing good or bad, and it's personal and different for everybody. I'm not saying all music is bad, cause actually I like that commercial music and is what I hear most of the times I won't lie, and other types of music too, but well...they are not for God, and a lot of times just for vain things, but of course you can enjoy yourself sometimes I think, is just that the purpose of music is for showing love to Him.
And bringing another subject here hehe, you would find very shocking how even the most "adorable" song is worshiping Satan in subliminal messages . Go to youtube and put high school musical songs, subliminal messages, YOU'LL BE SORPRISED, and not only them, almost all songs now have those messages,maybe not on purpose inicially, cause the ones that are singing don't know I think, but the people producing the songs are the ones who "convert" the lyrics, I was scared the first time I discovered it lol.
Isaiah 5:12
"They have lyre and harp, tambourine and flute and wine at their feasts, but they do not regard the deeds of the Lord, or see the work of his hands."
Peace
