First, it's a shock that God had rescued Israel's enemies in their own experiences of exodus. But it's also shocking that God would have been acting under the name of a pagan deity. As we know, these pagan deities were considered to be demonic in the eyes of Israel. How could such a thing even be imagined?
Well, for fans of C.S. Lewis our imaginations go to the The Last Battle, the final book in The Chronicles of Narnia.
I'll try to keep spoiler alerts to a minimum if you haven't read the book. The scene I'm referring to comes toward the end of the story. Narnia has been invaded by its pagan (in the Narnian imagination) neighbor, the Calormenes, who worship the god Tash, a malevolent and demonic deity. Among the invading Calormenes is Emeth, a Calormene solider. Emeth is a just and righteous man and is a devoted worshipper of Tash. In the eyes of Emeth, it was Aslan, the deity of Narnia, who was demonic and wicked.
Because of details I won't share here, Emeth finds himself in Aslan's country. And there, waking through its beauty, Emeth comes face to face with Aslan, the god of the Narnians. Emeth quails, expecting Aslan to kill him for being a follower of Tash. Instead, Aslam welcomes him as a son. This confuses Emeth. How can a loyal follower of Tash be a son of Aslan? Aslan explains it to him.
Later, the Pevensie children come across Emeth, and he shares his story and Aslan's explanation:
So I went over much grass and many flowers and among all kinds of wholesome and delectable trees till lo! in a narrow place between two rocks there came to meet me a great Lion. The speed of him was like the ostrich, and his size as an elephant’s; his hair was like pure gold and the brightness of his eyes like gold that is liquid in the furnace. He was more terrible than the Flaming Mountain of Lagour, and in beauty he surpassed all that is in the world even as the rose in bloom surpasses the dust of the desert.
Then I fell at his feet and thought, Surely this is the hour of death, for the Lion (who is worthy of all honour) will know that I have served Tash all my days and not him. Nevertheless, it is better to see the Lion and die than to be Tisroc of the world and live and not to have seen him.
But the Glorious One bent down his golden head and touched my forehead with his tongue and said, Son, thou art welcome. But I said, Alas Lord, I am no son of thine but the servant of Tash. He answered, Child, all the service thou hast done to Tash, I account as service done to me.
Then by reasons of my great desire for wisdom and understanding, I overcame my fear and questioned the Glorious One and said, Lord, is it then true, as the Ape said, that thou and Tash are one?
The Lion growled so that the earth shook (but his wrath was not against me) and said, It is false. Not because he and I are one, but because we are opposites, I take to me the services which thou hast done to him. For I and he are of such different kinds that no service which is vile can be done to me, and none which is not vile can be done to him. Therefore if any man swear by Tash and keep his oath for the oath’s sake, it is by me that he has truly sworn, though he know it not, and it is I who reward him. And if any man do a cruelty in my name, then, though he says the name Aslan, it is Tash whom he serves and by Tash his deed is accepted. Dost thou understand, Child? I said, Lord, though knowest how much I understand. But I said also (for the truth constrained me), Yet I have been seeking Tash all my days. Beloved, said the Glorious One, unless they desire had been for me thou wouldst not have sought so long and so truly. For all find what they truly seek.