Only be strong and very courageous, being careful to do according to all the law that Moses my servant commanded you. Do not turn from it to the right hand or to the left, that you may have good success wherever you go. This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success. Have I not commanded you? Be strong and courageous. Do not be frightened, and do not be dismayed, for the LORD your God is with you wherever you go.”
Joshua 1:7-9
A lot of things are working together in my life to make me think more strongly about evangelism. I’ve had discussions with close friends about the need to do evangelism, and for Churches to stop being content with their own self-existence and get on with the great commission we see at the end of the Gospel according to Matthew (28:18-20).
Then, in my daily Bible reading I came upon the above passage. I hope that the following rant is not an example of what Martyn Lloyd-Jones calls “having a pet theory” of the scriptures.
It strikes me that God says to Joshua twice that he is to be strong and courageous. The second time is the one that’s interesting to me here, “Have I not commanded you? Be strong and courageous. Do not be frightened, and do not be dismayed, for the LORD your God is with you wherever you go.”.
I think that the second command is actually more than just an imperative “you should be strong and courageous”, which seems a silly command if it’s just given out there. It’s like saying to someone “grow a third arm” or “fall in love with that girl over there”. The second time the command is given, it’s based partially on the statement that God has commanded it. What God is asking of Joshua here is not simply a willingness to screw up his courage and take the jump into leading Israel, but to trust God’s command as steadfast. What God commands is good, and in the power of God (and usually in the power of God alone) can be accomplished. This is why we see at the end of the statement the phrase “for the LORD your God is with you wherever you go”. There’s an implied proposition that Joshua should trust that the word of the Lord will stand firm and come to pass. That as Joshua remembers the Law and the acts of God and the precepts of God, he will see the faithfullness of God at work in the past and be able to trust God’s commands for the future.
But what does this have to do with evangelism and the great commission? Simply that we too have a command of God in Jesus Christ to go out into all the world and make disciples of all nations. That command is a sure one since it comes from God incarnate, and thus WILL come to pass.
Joshua had a land full of people in entrenched positions, and walled cities, and large soldiers which had scared his forefathers into not entering the land. We have a world here in the west overrun by secularism, entrenched in sin.
Yet as with Joshua, we have the promise of God Himself that the command He gives will come to fruition, we need only be used of God to do it as Joshua was. As Jericho fell, people’s souls can come to love and treasure God so much that they forsake their wickedness and earthly treasures.
Jesus ends the command in Matthew similarly to the way we see God ending Joshua’s commission in the Old Testament, “behold, I am with you always, even to the end of the age”.
We have the King of kings and Lord of lords giving us a command to go into the world and to make disciples, and we have his own promise that he will be with us in it. The work cannot be done by our power, but as with Joshua, we are not to trust in our power, but in God’s. His commands are not burdensome, and his word does not fail, so maybe we should start stepping out in faith, trusting in the word of God and his faithfulness in the past as a seal on what He can and will do through us to further His glory. Let us get to the task, after all, has he not commanded us? 
(considering) 8:28 