Unbelief is the only thing that can constrain the manifestation of God’s power in your life.
We tend to think that we believe in God. And yet, our actions betray our unbelief.
If you doubt, you don't believe. If you believe, you don't doubt.
If you really believed in God, you would act far differently than you do. Is this hard to believe? If you really believed God notices every sparrow that falls to the ground, could you ever be anxious or sad about your situation? Do you really believe that all things are done in the wisdom of he who knows all things? Do you really believe that God loves you?
If you really believed Jesus, you would always act exactly like him. Do you? You would keep all of his commandments as you understand them, even in the hardest moments. Do you? You would act like he acts, you would react like he reacts. Do you? You would feel how he feels, so far as you understand. Do you?
If your answer to any of these questions is no, look no further for the difference in the degree of miracles manifested in the scriptures compared to your life.
If your answer to any of these questions is no, it is time to reconcile yourself to God.
37 ...it is by faith that miracles are wrought; and it is by faith that angels appear and minister unto men; wherefore, if these things have ceased wo be unto the children of men, for it is because of unbelief, and all is vain.
38 For no man can be saved, according to the words of Christ, save they shall have faith in his name; wherefore, if these things have ceased, then has faith ceased also; and awful is the state of man, for they are as though there had been no redemption made. (Moroni 7)
The Lord said:
14 Come unto me, O ye house of Israel, and it shall be made manifest unto you how great things the Father hath laid up for you, from the foundation of the world; and it hath not come unto you, because of unbelief.
15 Behold, when ye shall rend that veil of unbelief which doth cause you to remain in your awful state of wickedness, and hardness of heart, and blindness of mind, then shall the great and marvelous things which have been hid up from the foundation of the world from you—yea, when ye shall call upon the Father in my name, with a broken heart and a contrite spirit, then shall ye know that the Father hath remembered the covenant which he made unto your fathers, O house of Israel. (Ether 4)
O then despise not, and wonder not, but hearken unto the words of the Lord, and ask the Father in the name of Jesus for what things soever ye shall stand in need. Doubt not, but be believing, and begin as in times of old, and come unto the Lord with all your heart, and work out your own salvation with fear and trembling before him. (Mormon 9:27)