Tosefta for Horayot 25:20

The measure [allotted] to anyone that teaches a single chapter to his fellow, the verse ascribes to him as though he formed him, and shaped him, and brought him into this world, as it is said (Jer. 15:19), "If you bring out the precious (yakar) from what is worthless, you shall be as My spokesman (lit., 'My mouth')" (JPS Tr.). For just as the selfsame mouth [of God] imbued Adam the first man with a soul, so too [as to] anyone who brings a single creation under the wings of the shekhinah, we ascribe to him as though he formed him, and shaped him, and brought him into this world. And "precious" (yakarah) is Torah (lit., "teaching"), as it is said (Prov. 3:15), "She is more precious than rubies; [All of your goods cannot equal her]," and it says (Prov. 20:15), "Gold is plentiful, jewels abundant, But wise speech is a precious object" (JPS Tr.).