Christian Theology in Plain Language, p. 219.
Non-Christians often ask the Christian, "But how can the God of love allow any of his creatures to suffer unending misery?" The question is, how can he not? The fact that God is love makes hell necessary.
"Hell," as E. L. Mascall once said, "is not compatible with God's love; it is a direct consequence of it." That was his way of stressing the fact that the very God who loves us is the one who respects our decisions. He loves us, but he does not force his love on us. To force love is to commit assault. He allows us to decide. He loves us, he encourages our response, he woos us, he pursues us, he urges us, but he does not force us, because he respects us.