Again, the devil took him to a very high mountain and showed him all the kingdoms of the world and their splendor; and he said to him, "All these I will give you, if you will fall down and worship me." Jesus said to him, "Away with you, Satan! for it is written, 'Worship the Lord your God, and serve only him.'" Then the devil left him, and suddenly angels came and waited on him.
This third and final temptation takes on a different nature than the first two. No longer does the devil say "if you are the Son of God." Instead he levels a temptation against the very foundation of the law, against the first commandment itself - idolatry. The account in Luke explains it a bit more: "all this glory and authority has been given to me and I give it to anyone I please." (Luke 4.6) Does not Jesus elsewhere call the devil "the prince of this world?" Us children of the household of the faith, living as we do in the world, must contend constantly with him, that is, the "spirit of the world."
We know that God is love, therefore the law was given out of love and for our good. Think then how important the first commandment is for us. "Worship God alone." It is impossible for us to be happy any other way. In fact it is impossible to have it any other way. "You cannot serve God and wealth." (Matthew 6.24)
Given the importance our God attaches to this it would be worth spending a lot of time reflecting on how we might be falling for the world or serving the spirit of our times instead of Him. Jesus shows once again the best way to do this and the solution to the temptation is the word, that is, He Himself - the Word.