Shemot 1:21

וַיְהִ֕י כִּֽי־יָרְא֥וּ הַֽמְיַלְּדֹ֖ת אֶת־הָאֱלֹהִ֑ים וַיַּ֥עַשׂ לָהֶ֖ם בָּתִּֽים׃ And [God] established households for the midwives, because they feared God.

Rashi

houses (dynasties) of the priesthood and the Levites and of royalty which are all termed בתים, “houses”, as it is said, (1 Kings 9:1) “and Solomon built the house of the Lord and the house of the king”: “the house of the Lord” i. e. a dynasty of priests and Levites — from Jochebed (Shifrah); and “the house of the king”, i. e. a royal dynasty — from Miriam (Puah), just as it is stated.

• God rewarded them for their good deeds: fearing god & not killing the babies(see: Shemot 1:17)
  • God made them cohens & levis
  • By "households" he meant respected dynasties