Of moment
Definition 1 of 1
Pro Tip 1/3Historical Importance
Refers to events or decisions that have lasting significance or impact in history. 
The speech was an event of moment in the civil rights movement.
Pro Tip 2/3Emotional Weight
Conveys a sense of gravity or seriousness due to the possible consequences involved. 
Her choice to move abroad was a decision of moment, affecting all her family.
Pro Tip 3/3Formal Speech
More often used in a formal context; may not be common in everyday, casual conversation. 
The committee will deliberate on matters of moment.