From Longman Dictionary of Contemporary Englishsomething is of the essencesomething is of the essenceused to say that something is very important Good communications are of the essence to remain competitive.time/speed is of the essence (=it is very important to do something quickly) → essence
Examples from the Corpus
something is of the essence• If you like the house the chances are that other people will like it too, so speed is of the essence.• Speed is of the essence when following up newspaper advertisements.• Speed is of the essence, especially when it comes to losing weight.• Superposition is of the essence of waves, which can be added together to reinforce or cancel each other out.• I understand why the Government have maintained an exemption for small businesses, for which survival is of the essence.• But time is of the essence.• As with every other aspect of the desert life cycle, time is of the essence.• It is clear that, in the development of the safety case regime, time is of the essence. 