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To redeem means to buy it back. We need to make the effort to buy back the time that the world would usurp to focus on Godly things. Here is a quote from an online commentary on Ephesians 5 which you can access at:
Ephesians 5:16 MAKING THE MOST OF EVERY OPPORTUNITY: "Redeeming the time" (KJV). "Exagorazo" = to buy out of the marketplace.
"Love, thankfulness, and knowledge of God: we never have enough. We never begin to have enough. The amount God will judge us by is the amount we could have developed in the time, opportunity, and ability He has given each one. Are we, as commanded, 'redeeming the time' -- every moment? Or are we wasting it in folly and self-pleasing? What a tragedy to appear at the judgment seat of Christ in our cute little play-suit, full of jokes and games, but with our lamps and minds dark and empty! Who dares contemplate the shame and the hopeless remorse?" (GVG).
"Time is not measured by the years we live, but by the deeds we do and the joys we give" (Helen Steiner Rice).
I hope you have found this helpful.