Ephesians 5:17

διὰ τοῦτο, Ephesians 6:13. Such being the need for watchfulness.

μὴ γίνεσθε ἄφρονες. Cf. Ephesians 5:7. ἄφρων is constant in the Wisdom literature for various Hebrew equivalents. It suggests the thought of moral recklessness. It is a characteristic of heathen society in 1 Peter 2:15. For the distinction between σοφία, φρόνησις, σύνεσις see on Ephesians 1:8 and Ephesians 3:4.

ἀλλὰ συνίετε. The opposite to insensate recklessness is quick discernment of the signs of God’s Will. συνίετε is constantly used of the power of spiritual apprehension, the understanding of Parables, &c., Matthew 13:10 ff., Matthew 13:19 &c.

τί τὸ θέλημα τοῦ κυρίου. Cf. Romans 12:2; Colossians 1:9. This is another way of expressing the thought of Ephesians 5:10.