The 40 days of lent is that because it celebrates the time that Jesus spent alone contemplating his journey. It encompasses the holy season that begins with Ash Wednesday and ends with Easter. The entire holy season pays tribute to Jesus' sacrifice for mankind, culminating with his death on the cross- but it should also be remembered how he spent his life in devotion to the cause. :-)
Also, historically it fits with a time of great fasting. This portion of the year was the hardest, food supplies were scarce and the lands were not ready to plant. Fasting for religious reasons helped people focus on better things, rather than dwelling on the fact they had no food to eat.
at 4:52 PM on Mar. 30, 2010