Deposit and Firstfruits
To describe the Spirit present in the church and at work in believers, all told, Paul uses a couple of metaphors, the one commercial, the other agricultural: the Spirit as a “deposit,” “down payment,” “guarantee” (ἀρραβών; 2 Cor 1: 22; 5: 5; Eph. 1: 14) 10 and as “firstfruits” (ἀπαρχή; Rom. 8: 23).
Richard Gaffin, In the Fullness of Time (Wheaton, IL: Crossway, 2022), 139