give (one) pause for thought
To cause one to take a moment to consider something. I'd love to buy a house, but the fact that I'd have to completely deplete my savings account to do it gives me pause for thought.
give (somebody) pause for ˈthought
, give (somebody) ˈpause
(formal) make somebody think seriously about something or hesitate before doing something: His remarks on the conditions in our prisons gave me pause for thought. Until that moment I’d never realized things were so bad.