Having foreordained us (Proorisas hēmās). First aorist active participle of proorizō, late and rare compound to define or decide beforehand. Already in Act 4:28; 1Co 2:7; Rom 8:29. See also Eph 1:11. Only other N.T. example in Eph 1:11. To be taken with exelexato either simultaneous or antecedent (causal).
Unto adoption as sons (eis huiothesian). For this interesting word see note on Gal 4:5 (included with discussion of Gal 4:4). Also see Rom 8:15; Rom 9:4.
Unto himself (eis auton). Unto God.
According to the good pleasure of his will (kata tēn eudokian tou thelēmatos autou). Here eudokian means purpose like boulēn in Eph 1:11 rather than benevolence (good pleasure). Note the preposition kata here for standard.