What is needed for happy effectual service is simply to put your work into the Lord's hand, and leave it there. Do not take it to Him in prayer, saying, "Lord, guide me, Lord, give me wisdom, Lord, arrange for me," and then arise from your knees, and take the burden all back, and try to guide and arrange for yourself. Leave it with the Lord, and remember that what you trust to Him you must not worry over nor feel anxious about. Trust and worry cannot go together.
Christians, who have given themselves into the care and keeping of the Lord Jesus, still continue to bend beneath the weight of their burden, and often go weary and heavy-laden throughout the whole length of their journey.
You find no difficulty in trusting the Lord with the management of the universe and all the outward creation, and can your case be any more complex or difficult than these, that you need to be anxious or troubled about His management of it?
It is not worrying, but rather trusting and abiding in the peace of God that will crush anything that Satan tries to do to us. If the Lord created the world out of chaos, He can easily deal with any problem that we have.
Knowing that God is faithful, it really helps me to not be captivated by worry. But knowing that He will do what He has said, He will cause it to happen, whatever He has promised, and then it causes me to be less involved in worrying about a situation.