According to the riches of his grace (kata to ploutos tēs charitos autou). A thoroughly Pauline phrase, riches of kindness (Rom 2:4), riches of glory (Col 1:27; Eph 3:16; Phi 4:19), riches of fulness of understanding (Col 2:7), riches of Christ (Eph 3:8), and in Eph 2:7 “the surpassing riches of grace.”
Which (hēs). Genitive attracted again to case of antecedent charitos.