[Ephesians] 1:13 Sealed, marked as God's property and assured of His protection. (Cf. 4:30; 2 Co 1:22)

[Ephesians] 1:14 Guarantee, literally "down payment," "first installment," which in ancient times was a substantial portion of the whole.

Martin Franzmann and Walter H. Roehrs, Concordia Self-study Commentary [commentary on Ephesians], p. 187