line one's pockets

To make a large amount of money for oneself in a way that is considered greedy or dishonest. The phrase typically implies that one is prioritizing making money above some other, more admirable goal. He doesn't care about creating some digital utopia—he's just trying to line his own pockets. This new contract is going to line our pockets for years.

Accept a bribe or other illicit payment, as in The mayor and his cronies found dozens of ways to line their pockets. This expression dates from the mid-1500s, when it was also put as line one's purse.

To accept bribes, or acquire money in some other questionable way. One writer claims that this term originated when a court tailor who wanted the patronage of Beau Brummel gave him a gift of a coat lined with banknotes. However, the term to line one’s purse, meaning to cram it full of gold or money, predates the eighteenth-century dandy by some two hundred years; Shakespeare used it in Othello (1.1), where Iago speaks of dishonest servants who “have lin’d their coats.”