Moses commanded the Israelites to stand still and watch the Lord fight for them. 
Some may see their part in Pharoah’s army’s defeat as non-crucial. But in actuality their obedience to do as the Lord commanded gave way to an undeniable victory for the nation and a platform for the power of their Lord to be made known among the neighboring countries. 
“Standing still and watching” will be the most effective if that’s what He has called you to do. 
Scripture taken from:

Exodus 14:13