1Ki 18:42 …And Elijah went up to the top of Mount Carmel. And he bowed himself down on the earth and put his face between his knees.
God promised Elijah that the 3 1/2 year drought would end. Ahab the king heard of the news and went up to eat and drink. Elijah the prophet on the other hand retired himself to pray the blessings through. The great burden of his prayer was for the rain that had been so long withheld.
God wills as demonstrated here but then what He wills He waits for it to be fetched by the aid of prayers. Think of it this way, God may call us to push the heavy rocks standing on the way but He does not expect us to move them. We push, He moves them and gets all the credit. Elijah cast himself down on his knees upon the earth, in token of humility, reverence, and importunity. Those who desire the abundance of rain will have humility, faith, seek God fervently in prayer, and patiently wait until He has moved.