Idiom
come by somethingcome by (something)
1.
to obtain money, wealth, or goods.
Mitchell had acquired some wealth, although whether he came by it honestly or dishonestly is not clear.
Usage notes: often used in the form hard to come by:
Fresh meat and fish were hard to come by.
2.
to learn a skill.
I had to work hard to learn to skate. I didn't come by it easily.