Still wet from His baptism by John in the Jordan, with the word of His Father still ringing in His ears, Jesus is led by the Spirit, the same Spirit that descended upon Him when He came up from the water, into the desert to be tempted by the devil.
The word devil (διάβολος) means slanderer. It's instructive that the evil one is described as a slanderer. It tells us how he works. What he seeks to do. What his endgame is. Slander is the utterance of false statements or reports about a person, or malicious misrepresentations of his actions, in order to defame or injure him (OED). Slander is false speech that ruins the reputation and good name of others. Slander makes the tongue one of the strongest and most lethal weapons. I gives the tongue ability to inflict damage upon the reputation, and thus upon the credibility of everything that is subsequently said and done.
Thus, the devil slanders God. He speaks falsely, challenging God's reputation, His good name, and thereby His Word, His promises, and His works. For when reputation is defamed so also is everything that the slandered says and does. And so it is that the temptation the devil uses against us is to slander God so that we don't trust Him: His Word, His promises, His works.
It is one of his primary tactics from the beginning: "Did God really say . . . ?" "Surely, you won't die." "If you are the Son of God . . . ." The devil challenges the Word and Work of the Father at Jesus' baptism. He seeks to defame God's good name and reputation as the one who is love and does everything out of that love. He uses the tongue to damage God's credibility. He calls into question what is said and done by the Lord. He wants Jesus to doubt and act on that doubt. The only way to fight it is to use the same weapon, to use the tongue, with God's Word and Work firmly placed upon it to put the devil in his place. To counter the false report, the malicious misrepresentation with the truth found in God's Word, His promises, and His works.
He does the same to us but in a different way. He slanders God by questioning whether we are God's children not by getting us to do something but based upon what we have already done or left undone. He slanders God by showing us that we have slandered God in our thoughts, words, and deeds. He shows us that our sin, our rebellion slanders what God has said about us, the way that the Prodigal Son slanders his father when he asks for his inheritance. The devil tempts us by showing us that we are part of the problem. That we, too, are slanderers, not just him. He says: "If you are a son of God, why do you not honor your father and mother?" "If you are a son of God, why do you have so much lust and greed and envy? Why do you speak ill of your neighbors? Why do you grumble about having to come to church to meet God and receive His gifts of eternal life? The devil points out that because of our sin, we slander God's good name and reputation. We call Him a liar with our deeds, with the way we treat one another. Is not all sin a defamation of His Name? The very Name He placed upon us in Holy Baptism? Is not all sin a disparagement of His Word and Work?
The devil is real. But he likes to hide behind us, using us like human shields or as suicide bombers. He's real but he's also a coward. He's on the retreat. He's lost. The battle is over. The Victory is won. This is his last ditch attempt, out of desperation with no hope of success. And it's a good thing we undergo this temptation. It's a good thing we endure the fight. "For where there is no enemy, there is no fighting; where there is no fighting, there also is no victory; where there is no victory, there also is no crown" (Gerhard, Postilla, I:222). If we endure no fighting, no temptation, then we have no enemy. That means that we have already lost and are on the wrong side.
But we endure temptation. We do fight. We have an enemy. It is the devil, the world, and our sinful nature. We know who we're fighting against. And we know that we've already won because Christ is risen. He has fought in our stead. And He is victorious. He holds the keys to death and the grave. He has the Words of eternal life. He is the bread of God's Word that came down from heaven, so that when we eat of Him we have forgiveness of sin, life, and salvation. And with this bread, this Word, on our tongues, we confess the truth, we sing His praise. For in Him we, too, are victorious. In Him, We have an imperishable crown.