come knocking at (one's) door(redirected from comes knocking at their doors)
come knocking at (one's) door
To present (itself) to one as a possibility in the near future, especially temporarily. Usually refers to opportunities or desirable options. It was hard leaving my parents and all my friends from high school, but when an opportunity to attend school in Europe came knocking at my door, I knew I had to seize the chance. What would you do if the chance to make half a million dollars suddenly came knocking at your door?