What does it mean to redeem the time?

To redeem the time is literally to buy it back. The phrase comes from exagorazo, to ransom or buy, to recover something out of the power of another by paying a price, and the picture is the agora, the ancient marketplace, which stands for the world, the devil's domain. As Jesus redeemed us, so now we are to redeem time: every morning God lays before us twenty-four hours and gives us the opportunity to buy out as much of that time as we will for eternity. Every minute we spend in fellowship, filled by means of the Spirit, belongs to us forever, and every minute out of fellowship is lost.