'First born' in the Bible

So he smote, Every first-born in Egypt, The beginning of their strength, in the tents of Ham;

Yea, I, will appoint him, firstborn, Most High to the kings of the earth!

Then smote he every firstborn in their land, The beginning of all their strength;

Who smote the firstborn of Egypt, both of man, and of beast;

To him that smote Egypt in their firstborn, For, age-abiding, is his lovingkindness.