OK, I admit it. I've been stuck in the first two verses of chapter four. This is our third week feeding at the same spot. Either that is caused by the leading of the Holy Spirit or I'm just mentally obtuse. You'll have to be the judge of that. Next Sunday we'll move on to the rest of the chapter. We've wandered around in a lot of details but the big idea in the last part of chapter three and the first two verses of chapter four is easy to state. God's Word brings no benefit to the hearer unless that hearing is a hearing mixed with faith: Hebrews 4:2 (ESV) - "For good news came to us just as to them, but the message they heard did not benefit them, because they were not united by faith with those who listened."
The people being referenced in these verses are the Israelites at Kadesh. God speaks to them about going into the promised land. It is a good land and He will supply their needs. Only Joshua and Caleb hear this word from the Lord with faith. The rest - 600,000 people - an entire unbelieving generation - die under God's judgment in the wilderness. They never enter God's promised land. They didn't hear God's word with faith.
Such is the importance of hearing the Word with faith. It is not enough to believe an event in God's Word actually happened. It is not enough to believe a statement in God's Word is actually from God. It is not enough to agree that what God has spoken is true. Mental agreement is not the same as the hearing of faith.