Doesn't make much sense to me, are you sure you heard it right?

It means 'what it is has got to be what it is.' Bob Marley is (was) Jamaican and he would sing (and speak) in Jamaican creole. To understand these sentence structures you have to have some knowledge of creole languages/dialects. It's okay that you don't, though. Just be aware that they often don't follow the language patterns of standard English and these languages/dialects have their own grammar and rules.

Thank you all for your earnest help. I learn a lot from your explanation. Yes, Gary. I checked the spelling of words and marks one by one. I read this sentence from a quote APP.

western songs are often of no use for English language learners. Although many songs that seem to make no sense are written in Standard English and these are the songs that last and are remembered for many generations. For this Bob Marley song written in Jamaican Creole,​ it most likely means Hey Mr Music what has to be has to be it has to be. Another important thing to remember about western pop songs is that often they are grammatically meaningless and are just written to provide a rhyming sound. In western pop songs, the rhyme (but often no sensible meaning) is Important. In other cultures, this is not so, therefore in some cultures songs are more useful to language learners.

According to http://www.metrolyrics.com/rainbow-country-lyrics-bob-marley.html, you have written it incorrectly. You also need to keep the punctuation - it's essential to understanding.