There are a lot of essentials in life- for instance:
If you are going to make bread, you must have dough.
If you are going to fly 30,000 feet above the ground it is essential to have an airplane.
If you are going to fish, you must have bait.
If you are going to speak, you must have vocal cords.
If you are going to think, you must have a brain.
If you are going to drive you must have a valid license.
If you are going to make a phone call, you must have a phone line.
If you are going to eat, you must have food.
His presence is essential if we are going to know success in the Christian life.
Anon