But Pilate said to them, “Why, what evil has He done?” But they shouted all the more, “Crucify Him!” Wishing to satisfy the crowd, Pilate released Barabbas for them, and after having Jesus scourged, he handed Him over to be crucified. (Mark 15:14-15 NASB)
There are those dear to me who, in their inquiry into the claims of Christianity, stumble over the idea of a God who would slay his own Son—especially by the agony of crucifixion. And because they are so very dear to me I will do my best to give an answer. Whether or not it proves satisfactory remains questionable for I have sometimes found that objections to Christianity are not always what they seem on the surface but reflect something more deeply rooted. I am also keenly aware how limited our (and my own in particular) insight is into the fathomless wonder of God. As a close friend of mine so succinctly puts it, “All I know from personal experience and investigation is that God is incredibly good, does things with incredible kindness, and intends things only incredibly loving – the rest, to me, is a mystery.” What follows, therefore, is simply my own sense of the question at hand as best I grasp it.
Why Crucify Your Son (PDF)