2 Corinthians 8:9

γινώσκετε γὰρ κ. τ. λ.: for ye know the grace, i.e., the act of grace, of our Lord Jesus Christ, that being rich, sc., in His pre-existent state before the Incarnation, yet for your sakes (cf. Romans 15:3) He became poor, sc., in that κένωσις which the Incarnation involved (Philippians 2:5-6), (the aor. marks a def. point of time, “He became poor,” not “He was poor”), in order that ye by His poverty, i.e., His assumption of man's nature, might be rich, i.e., in the manifold graces of the Incarnation (cf. 1 Corinthians 1:5). This verse is parenthetical, introduced to give the highest example of love and self-sacrifice for others; there is nowhere in St. Paul a more definite statement of his belief in the pre-existence of Christ before His Incarnation (cf. John 17:5). It has been thought that ἐπτώχευσε carries an allusion to the poverty of the Lord's earthly life (Matthew 8:20); but the primary reference cannot be to this, for the πτωχεία of Jesus Christ by which we are “made rich” is not the mere hardship and penury of His outward lot, but the state which He assumed in becoming man.