Creativity also encompasses using already existing materials in a unique and creative way. Pairing those words with that music created a song with some staying power. It's sort of like sampling or remixing a song etc. As long as the they're not taking credit for the original source material, it's definitely creative.
Yes, I find the writer creative because he took words that were not set to music and turned them into lyrics. It is a very popular song that most people know, and I am impressed with anyone who can find success in the art world. The writer is truly accomplished.
The lyrics to The Byrds' song are penned by someone creative. Good lyricists often incorporate themes from traditional literature or other works. Using prose from a biblical book is yet another way to generate a work. These lyrics remind the listener that there are purposes to life and these purposes may differ depending on the event.
It is not really creative if you take a bible verse and make a song out of it, word for word. Technically, whoever "wrote" this song, didn't really write it. They just took the words from the Bible and re-arranged them. The only real creativity is the music written for the song.