Jesus was fully human. He needed food as much as we do.  However, His time of fasting was not an endurance exercise; it was dedicated to communicating with His Father in preparation for His first big spiritual battle.  As always, Satan thinks he can find an easy path with those who are physically weak.  Jesus was really hungry and empty, but on the other hand, He was hungry to see God's righteousness and so His spirit was full (Matthew 5:6).

Satan's temptation appeared to come at a physical level: the need for hunger to be satisfied.  But the real test was to get Jesus to exploit His divinity for His human needs.  Of course, Christ could have produced bread from stones, but He refused.  His needs would be met by His Father; Satan had no right to interfere.  Nor did Jesus need to prove who He was, either to Himself or to Satan.  He knew that He was God the Son and that His mission was to defeat Satan.

Satan tempts us by using lies to deceive us into wrongly thinking that we are justified in getting what we want for ourselves, even if that means disobeying God's Word.  Jesus used true words to put Satan in his place.  He quoted from Deuteronomy 8:3, ‘He humbled you, causing you to hunger and then feeding you with manna, which neither you nor your fathers had known, to teach you that man does not live on bread alone but on every word that comes from the mouth of the LORD.’  In other words, it is God who has the right to say when and how our needs will be met - not ourselves, anybody else and certainly not Satan.

Jesus' stomach may have been empty, but His heart was full of God's Word.  He was satisfied with His relationship with the Father.  That is the right condition in which to resist the devil's temptations.  Jesus quoted Scripture because the Word of God is the sword of the Spirit (Ephesians 6:17), and is the only weapon with which we can attack Satan and unmask his lies.  Unless we practise communication with God, and develop a hunger to know His Word, we are easy prey for the tempter.  But when we desire the Lord's Will more than anything else, and rely on His Word to inform our decisions, then we will be able to see through the temptations and not be fooled into agreeing with Satan's lies. It is God's Word alone which is definitive truth, and we should use it to disarm the tempter’s power.