Tao te Ching

27 Good deeds leave no signs. Good words leave no flaws. Good scheme needs no deliberate plans. A good lock uses no bolts, yet it cannot be opened. A good knot uses no rope, yet it cannot be united. Hence, a saint is always kind by saving other people and rejects no one. He is always kind by saving all things and therefore nothing is being rejected. This is the true enlightenment. Thus, a kind person is the teacher of the unkind. An unkind person is a lesson for the kind to learn. He who does not value his teacher and dislikes the valuable lesson, although knowledgeable, is in fact greatly confused. This is the fundamental essence.