Dhp 326-328 · The Elephant
This mind of mine went formerly wandering about as it liked, as it listed, as it pleased; but I shall now hold it in thoroughly, as the rider who holds the hook holds in the furious elephant. Be not thoughtless, watch your thoughts! Draw yourself out of the evil way, like an elephant sunk in mud. If a man find a prudent companion who walks with him, is wise, and lives soberly, he may walk with him, overcoming all dangers, happy, but considerate.