'Firstling' in the Bible

and thou hast taken the Levites for Me (I am Jehovah), instead of every first-born among the sons of Israel, and the cattle of the Levites instead of every firstling among the cattle of the sons of Israel.'

every one opening a womb of all flesh which they bring near to Jehovah, among man and among beast, is thine; only, thou dost certainly ransom the first-born of man, and the firstling of the unclean beast thou dost ransom.

Only, the firstling of a cow, or the firstling of a sheep, or the firstling of a goat, thou dost not ransom, holy they are: their blood thou dost sprinkle on the altar, and of their fat thou makest perfume, a fire-offering of sweet fragrance to Jehovah,