Exodus 15:25 New International Version (NIV)

²⁵ Then Moses cried out to the Lord, and the Lord showed him a piece of wood. He threw it into the water, and the water became fit to drink.

There the Lord issued a ruling and instruction for them and put them to the test.

2 Kings 4:41 New International Version (NIV)

⁴¹ Elisha said, “Get some flour.” He put it into the pot and said, “Serve it to the people to eat.” And there was nothing harmful in the pot.

2 Kings 6:6 New International Version (NIV)

⁶ The man of God asked, “Where did it fall?” When he showed him the place, Elisha cut a stick and threw it there, and made the iron float.