'First fruit' in the Bible

Reuben, you are my oldest son, the first-fruit of my strength, first in pride and first in power:

You are to put on one side for the Lord every mother's first male child, the first-fruit of her body, and the first young one of every beast; every male is holy to the Lord.

And if the first-fruit is holy, so is the mass: and if the root is holy, so are the branches.

And say a kind word to the church which is in their house. Give my love to my dear Epaenetus, who is the first fruit of Asia to Christ.

Which is the first-fruit of our heritage, till God gets back that which is his, to the praise of his glory.