Of the essence
Definition 1 of 1
Pro Tip 1/3Urgent Contexts
Used when there's a tight deadline or something needs to be done quickly. 
To save lives, immediate response is of the essence.
Pro Tip 2/3Not Always Literal
Sometimes it's used figuratively to stress the importance of something, not just time. 
For this recipe, fresh ingredients are of the essence.
Pro Tip 3/3Business Deals
Common in negotiations, where timely decision-making can be critical. 
In the trading world, speed is of the essence.