Genesis 1:3 And God said, Let there be light: and there was light. (KJV)
Read Genesis and notice how over and over again you read, "God said." God does not create as we do. We must conceive, design, and manipulate matter to create. God simply speaks. His word has power of creation.
Isaiah 55:11 So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it.
This is the difference between the Word of God and the words of man. Our words are filled with doubt and uncertainty. We say "try" or "maybe" or "perhaps" about something. Yet, even when we state something with presumed certainty, the words contain no inherent power. But God's word has absolute integrity and because of that has the very power of creation within it. When God speaks, reality is. If God's word did not have this integrity, the world itself would not remain, if it existed at all. When God has spoken something, we can rely with complete confidence that it is true. It is this integrity of God's word that is the basis of our faith.
John 1:1-5 In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made. In him was life; and the life was the light of men. And the light shineth in darkness; and the darkness comprehended it not.
Jesus is that Word of God made flesh. Within Him is that complete integrity and the very power of creation. When Jesus spoke a thing, it was true. If He said, "Heal" then healing was. If He said, "Raise from the dead" the dead became alive. When He cursed the fig tree, it withered and died.
Mark 11:21-22 And Peter calling to remembrance saith unto him, Master, behold, the fig tree which thou cursedst is withered away. And Jesus answering saith unto them, Have faith in God. (KJV)
Mark 11:21-22 And Peter remembering, said to him: Rabbi, behold the fig tree which thou didst curse is withered away. And Jesus answering, saith to them: Have the faith of God. (Douay-Rheims)
I have quoted this verse twice to show you something. Note that the King James translation says "Have faith in God." The Douay-Rheims says "Have the faith of God." I have compared several English translations of this passage and some say "faith in God" while others say "faith of God." I don't claim to be a great scholar of the ancient languages, but from what I understand, "of" is the correct word here. Otherwise, what Jesus said next doesn't make any sense.
Mark 11:23-24 For verily I say unto you, That whosoever shall say unto this mountain, Be thou removed, and be thou cast into the sea; and shall not doubt in his heart, but shall believe that those things which he saith shall come to pass; he shall have whatsoever he saith. Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them.
This is one of those really difficult sayings of Jesus. It looks like we could just really, really believe something, say it, and then it would be true. That just doesn't happen though does it? In order for my word to have any effect, then the word I speak, must be with the same integrity as God's word. I have to have the faith of God in order to declare something and have it be so. Well, I can't be God! So, how can this be possible?
Galatians 3:26-28 For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ.
Romans 8:9-14 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness. But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you. Therefore, brethren, we are debtors, not to the flesh, to live after the flesh. For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live. For as many as are led by the Spirit of God, they are the sons of God.
Putting the statements of Apostle Paul together with what Jesus said, finally we can understand. It is not my faith in my word that has any power. It is my faith in God's Word that has power. I cannot simply declare a thing to be because I want it to be so. But, if the spirit of Christ fills my being, then the desires of His Spirit become my desires. I do not speak my words; His word speaks through me. Going back to Mark 11, a better understanding would be, "have faith in the power of God's word working through you." When we speak our words, there is no power. When we speak His word, the integrity of that word changes the world. Jesus as the Word of God made flesh had that power. When we, by faith, are baptized in the spirit of Christ, the same power flows though us.
Romans 10:8 But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach;
1 Corinthians 2:4-5 And my speech and my preaching was not with enticing words of man's wisdom, but in demonstration of the Spirit and of power: That your faith should not stand in the wisdom of men, but in the power of God.
And so, we come again to this truth: The just shall live by faith.