The word of God doesn't come to us in vain but to fulfill a purpose for which it was sent. There is a great power inherent in the word of God. God's word has the power to bless, heal and to deliver us.
God's word always produces results anytime we receive it and not just receiving it but receiving it by faith. We activate the power of the word when we mix the word with faith.
For indeed we have had the glad tidings [Gospel of God] proclaimed to us just as truly as they [the Israelites of old did when the good news of deliverance from bondage came to them]; but the message they heard did not benefit them, because it was not mixed with faith (with the leaning of the entire personality on God in absolute trust and confidence in His power, wisdom, and goodness) by those who heard it; neither were they united in faith with the ones [Joshua and Caleb] who heard (did believe).Hebrews 4:2
The good news was actually preached to the people of the old(the Israelites) but it did not been fit them in anyway because of their unbelievers.
Despite all the miracles that God performed before their eyes they still doubted His power, wisdom amd goodness when they we're left alone for a brief moment by God.
Again they doubted God and considered his outstretched arm as weak and unable to deliver them from their enemies when they heard news about them form the ten spies.
They we're never united in faith with Joshua and Caleb and as result perished in the wilderness and never got to the promised land.
People often complain of not getting the results needed after hearing the word of God and that's because they never mix the word with faith.
To mix the word with faith means to act on the word by faith, to activate God's power at work you must have faith in what it says.
In Luke Chapter 5 Jesus had a crusade at the lake of Gennesaret and preached to the multitudes. Peter was around and heard the Gospel as well. After the sermon Jesus told him to launch out into the deep for a great catch.
This was a man who was so experienced on the sea and knows every nook and crannies where the fish could be hiding but had failed after working throughout the night and caught nothing. He never doubted but act of the word by faith and got a remarkable results in his entire career.
And it came to pass, that, as the people pressed upon him to hear the word of God, he stood by the lake of Gennesaret, And saw two ships standing by the lake: but the fishermen were gone out of them, and were washing their nets. And he entered into one of the ships, which was Simon's, and prayed him that he would thrust out a little from the land. And he sat down, and taught the people out of the ship. Now when he had left speaking, he said unto Simon, Launch out into the deep, and let down your nets for a draught. And Simon answering said unto him, Master, we have toiled all the night, and have taken nothing: nevertheless at thy word I will let down the net. And when they had this done, they inclosed a great multitude of fishes: and their net brake. Luke 5:1-6
We should not give any room for doubts concerning what the word of God says. Doubts often surpress the power in the word and makes it powerless and resultless in our lives just like it happened to the Israelites who doubted and never got to the promised the land which was their heaven. We can also miss heaven or good things the Lord has promised us we don't mix the word with faith.