To be the top priority in a particular situation. If you're sick, then you should definitely stay home and rest—your health comes first. Our customers' needs always come first.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
come ˈfirstbe treated as the most important person or thing in somebody’s life: His work always came first with Joe, which upset his wife a lot.
Farlex Partner Idioms Dictionary © Farlex 2017