The word בית takes on various meanings in different Biblical verses. See בית for a general discussion of the assorted definitions of the word itself and the expression "עשה בית". The analysis below will focus on the possible meanings and purposes of the בָּתִּים in our verse, and the ramifications for the identification of the subject and object of the verse:
The "בָּתִּים" are literal brick and mortar houses. The commentators who take this approach have widely diverging opinions regarding the purpose of these homes:
To Benefit the Midwives
God or the Israelites made the homes for the benefit of the midwives. This possibility subdivides as to their purpose:
Subject of וַיַּעַשׂ – According to Radak, God supplied the houses. In contrast, the Tzeror HaMor says that the houses were built by the Israelites.
Object of לָהֶם – The houses were made for the midwives. This approach needs to explain that the masculine form "לָהֶם" can also refer to females2 – see Gender Forms.
Nature of the בָּתִּים – They were safe houses, rather than regular houses. Radak mentions a parallel case in Yirmeyahu 36:26 in which Hashem hid Yirmeyahu and Barukh from the king's messengers, while Midrash HaGadol notes the similarity to the story of Rachav hiding the spies from the king of Yericho (Yehoshua 2).
Context – The making of the houses explains the meaning of God's beneficence to the midwives in the previous verse.
The Egyptians – According to the Lekach Tov, Egyptians were relocated to houses amidst the Israelite population to spy and enforce Paroh's decree. The difficulty with this option is that the Egyptians are not mentioned until the following verse.
The midwives – Chizkuni suggests that the midwives were assigned special housing so that the Israelite mothers would find them easily.
The Israelites – The Ma'asei Hashem maintains that the Israelite population had overflowed from Goshen to the fields by the Nile, and Paroh built urban housing for them so that the midwives would be present for the delivery of the babies.
Nature of the בָּתִּים – Regular houses.
Families or Dynasties
The "בָּתִּים" are families or dynasties – see בית for a discussion of parallel verses.7
The Israelites or midwives were blessed with large families:
As a result of the midwives' actions, the Israelite population continued to grow.
Subject of וַיַּעַשׂ – Hashem, through the actions of the midwives.
Object of לָהֶם – The Israelites.
Nature of the בָּתִּים – A household.
Context – According to this approach, this verse recapitulates the description of the nation multiplying already found in the previous verse, and is the backdrop for Paroh's subsequent decree in the following verse.
The midwives themselves were blessed with large families.
Who are the Midwives – By identifying the midwives with women known from other Biblical stories,12 these commentaries are able to propose various combinations of kingship, priesthood, Levitehood, and leadership, as the dynasties referred to in the verse.13