John 14:12-14

I assure you and most solemnly say to you, anyone who believes in Me (as Savior) will also do the things I do; and he will do even greater things than these. And I will do whatever you ask in My name (as My representative), this I will do, so that the Father may be glorified and celebrated in the Son. If you ask Me anything in My name (as My representative) I will do it. 

Jesus gave us the authority to act as His representative here on earth. When we believe that this authority has been given to us, we will speak in accordance with His example and Word. That means we are to speak against lack, sickness, depression, and whatever is plaguing our lives and command it to leave in Jesus’ name.