You want to upload a piece of music on your blog, or write a post about a song’s lyrics. Nothing wrong with that. If you now of course how to it properly.
Music and lyrics too are subject to copyright law because they constitute intellectual property. Pieces of lyrics should be treated as any other piece of written text.
The ideal and most proper thing to do would be to come in contact with the musician or his agent and ask for his permission to use his music and lyrics. They may say yes, yes on conditions, no or just ignore you.
But let us be honest with ourselves: it is highly unlikely that anyone would go into such lengths. What should you do then?
It is time for risk assessment, something we indeed do every day but do not realize it. Take some time and start thinking: is the portion of lyrics you want to quote or the song you want to upload really going to be considered a breach of an artist’s intellectual property rights? Consider how important the lyrics are to the piece as a whole. Consider if the artist or his contract company have filed similar legal disputes in the past. Look at the context in which you are quoting or incorporating their lyrics, then make your own mind up. Only a lawyer can inform you about the exact risks you take when you upload music but if you do not want to get involved further, you take full responsibility
Of course, you can make a compromise and just include in your post a link to the artist’s official Youtube channel which complies with intellectual property law. Yes, it might not be the same as having the video ready-made for the reader to see, but try to urge them to click on the link and enjoy.