50 The verb קָרָא (qara’) followed by the lamed (ל) preposition has here the nuance of “summon.” The same construction is used later when Pharaoh summons Moses.
51 The second verb in Pharaoh’s speech is a preterite with a vav (ו) consecutive. It may indicate a simple sequence: “Why have you done … and (so that you) let live?” It could also indicate that this is a second question, “Why have you done … [why] have you let live?”

In other versions

So the king of Egypt called the midwives and said to them, “Why have you done this, and let the male children live?”

Then the king of Egypt summoned the midwives and asked them, “Why have you done this? Why have you let the boys live?”

So the king of Egypt summoned the midwives and asked them, “Why have you done this and let the boys live?”

So the king of Egypt called for the midwives. “Why have you done this?” he demanded. “Why have you allowed the boys to live?”

And the king of Egypt summoned the midwives, and he said to them, “Why have you done this thing and let the boys live?”

And the king of Egypt called for the midwives, and said unto them, Why have ye done this thing, and have saved the men children alive?

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