Tao Te Ching · Ch. 27

善行無轍跡;善言無瑕謫;善數不用籌策;善閉無關楗而不可開;善結無繩約而不可解。是以聖人常善救人,故無棄人;常善救物,故無棄物。是謂襲明。故善人者,不善人之師;不善人者,善人之資。不貴其師,不愛其資,雖智大迷,是謂要妙。

Shàn xíng wú zhé jì; Shàn yán wú xiá zhé; Shàn shù bù yòng chóu cè; Shàn bì wú guān jiàn ér bù kě kāi; Shàn jié wú shéng yuē ér bù kě jiě. Shì yǐ shèng rén cháng shàn jiù rén, gù wú qì rén; Cháng shàn jiù wù, gù wú qì wù. Shì wèi xí míng. Gù shàn rén zhě, bù shàn rén zhī shī; Bù shàn rén zhě, shàn rén zhī zī. Bù guì qí shī, bù ài qí zī, suī zhì dà mí, shì wèi yào miào.

Good traveling leaves no wheel-ruts or footprints; good speech has no flaws or reproaches; good counting uses no tallies or chips; good closing needs no bolts yet cannot be opened; good tying needs no cords yet cannot be undone. Therefore the sage is always good at saving people and abandons no one; is always good at saving things and abandons nothing. This is called following the inner light. Therefore the good person is the teacher of the one who is not good; the one who is not good is the material for the good person. To not value one's teacher, to not love one's material — though one be clever, this is a great delusion. This is called the essential wonder.

— Tao Te Ching 27

Source: Wang Bi edition (Chinese) + Hanyu Pinyin transliteration