Q. Why did God create wasps and spiders which are of no use?
R. Once upon a time David was sitting in his garden and he saw a wasp eating a spider, and there came a fool with a stick in his hand, and he drove them away. Then David said, "O Lord of the Universe, what benefit is there in these creatures? The wasp eats up the honey and is destructive; the spider weaves the whole year and there is nothing with which to clothe oneself; the fool only hurts people, and he does not know thy unity and thy greatness, the world has no benefit from him." The Lord replied and said, "David, thou dost scoff at these creatures now, but a time is sure to come when they will be of use to thee, and then thou wilt recognise the reason of their creation."
It happened thereafter, when he hid in the cave, being pursued by Saul, a spider came and made his web across the mouth of the cavern. Saul coming up, saw the web and said, "Certainly no man has entered this cave, as otherwise that web would have been torn to pieces." So he went away without searching the cave. When David came out, and beheld the spider, he kissed it and blessed it and said, "Lord of the Universe, who can accomplish works like any of thy works? For all thy deeds are beautiful."
When he came to Achish, David simulated the fool before him and his men. The daughter of Achish also was foolish and mad. When they brought David before him, he said to his men, "Are ye mocking at me, considering that my daughter is a fool, or am I in want of lunatics?" So they left him and he fled. When he found himself in safety he thanked God for all that he had made, for it was all beautiful.
When David (had entered the cave) he found Saul sleeping his noon-day sleep. Abner slept across the opening with his legs bent. David tried, slipped through the legs, and went in and took the jug of water. When he returned Abner suddenly stretched out and kept David as in a hedge, as if two heavy pillars had come down upon him. Then David prayed for God's mercy and said, "My God, my God, why hast thou forsaken me?" In that hour a miracle was performed for him, for a wasp came and stung Abner in his leg. He lifted it up and David was able to escape. Then David praised and thanked God.
It is not fit for man to mock or scoff at God's works (f. 24 a-b).