I think that lays it out pretty clearly here.
We have Christ as our example of being faithful; and then we have the man Moses who is also faithful. We can look at both examples. They are wonderful examples. But Moses led the people into the wilderness to bring them into the Promised Land, a type of our journey to the Kingdom of God. And these people heard the gospel, as we see in chapter 4, verses 1 and 2 there. They heard the gospel, but they did not mix it with faith. They did not believe the gospel that was preached to them. They did not believe the truth of what God was doing with them.
And so what did they do? They rebelled, they disobeyed. And God said, Ok, if this is the way you're going to be, you're all going to die in the wilderness. So He destroyed them and they did not enter His rest. Paul tells us, let us take a look at this example and learn something from it. And the thing we need to learn from it is that we have heard the gospel, we have to mix it with faith, that is, we have to take what we have heard, be faithful, and obey God. Do the things that He wants us to do, in fear that we will not make it, so that we will make it. And be diligent about it! Have some zeal!
That is what He wants us to do. Take what we have learned, and what we continue to learn, mix it with faith, that is, trust and confidence in God that He can get you where He needs you to be and where you want to be, which is the Kingdom of God. Trust Him that the instructions that He gives you in the Bible are apt for your situation. What you need to do, how you need to be, what your attitude needs to be, and do it, obey it, follow it.
And you know what that is going to do? That is going to land you in His rest. The Promised Land is yours. God will not destroy you in the wilderness. The Kingdom is open to you. Hear the gospel, add some faith, follow the instructions, enter His rest. Sounds easy, does it not? We know it is not. But that is the formula. Hear, faith, follow, firstfruits. Simple to say; hard to do. But that is the general formula.
Let us finish in Hebrews 4 and get the conclusion that Paul came up with when he made these statements about the ones dying in the wilderness and their bones being strewn about the desert. And so he has a conclusion for us.
We could do it. We can enter that rest. We can go forward without falling into that same example because God is with us.