Make it (one's) business to (do something) spoken language verb phrase
To decide to do something that does not directly concern one.
I know it's your life but I still want to make it my business to advise you about that thing.
I make it my business to clean that rubbish because everyone has the responsibility to protect the environment.
Seeing a lost kid in the mall, I made it my business to take him to find his parents.
I made it my business to call 911 when I saw a man get stroked on the street.
It is mostly used in the present tense.