[2:179] In retaliation there is life for you, O people of pith, so that you might fear.
In carrying out the retaliation there is life because when one knows that if he kills, he will himself be killed, he refrains from killing. In that there is life for the one who kills and the one who is killed.
But in abandoning retaliation, according to the allusive explanation, there is greater life because when one has been annihilated in Him (s), He is the successor for him and his life from Him is more perfect for him than his remaining with himself. When God has inherited from them and succeeded them, the remaining of the Successor is dearer than the life of the one who was annihilated.