The desert is seen as a place of foreboding. It is a place of danger and where one can find it difficult to live and survive. In the desert we can be attacked by hunger, thirst, heat, cold, and wild animals. We can also get lost in the desert.
There is also the desert within where we can be faced with our own personal difficulties and of course our own sins. These can be unpleasant and facing them can challenge us and take us out of our comfort zone.
Jesus goes into the desert after he is baptized as a preparation for his public ministry. He is fortified by the Holy Spirit. He fasts and prays while he is there and in a physically weakened state he is tempted by the devil.
In Matthew's Gospel we see Jesus tempted in three ways; the first is to trust no longer in God's providence... "Tell these stones to turn to bread." The second temptation about putting God to the test. "If you are the Son of God, throw yourself down.." The third temptation is to compromise the unique place of God in our worship. "I will give you all of these, if you fall at my feet and worship me."
While Jesus is physically weak and tired, he is morally and spiritually strong. When we go into the desert, when we give up something or take on some self-sacrifice for Lent, we become morally and spiritually strong.