Why forty days of Lent?

Those who recount the history of Lent say that it has not always been for 40 days, though the symbolic number seems fitting. Interestingly, the Talmud records that there was a long-standing plot on the part of Jewish leaders to take Jesus’ life:

For forty days before the execution took place, a herald went forth and cried, ‘He is going forth to be stoned because he has practised sorcery and enticed Israel to apostacy. Any one who can say anything in his favour, let him come forward and plead on his behalf.’ But since nothing was brought forward in his favour he was hanged on the eve of the Passover! – Sanhedrin 43a

The Talmud mentions that the public declarations of intent to kill Jesus began forty days beforehand – the traditional length of time for which Christians now observe the Lenten Fast. Or as the records of Jesus' followers mention,

But the chief priests, the teachers of the law and the leaders among the people were trying to kill him. (Luke 19:47; there are others like it)

This is the traditional time of year to focus on Christ's death and our own joining our death to his by dying to sin now.