Ephesians 5:16 commands believers to be "redeeming the time, because the days are evil." The Greek word for time here — kairos — is not chronological time (kronos) but appointed time, the time with specific opportunity built into it. The word "redeeming" — exagorazo — means to buy back, to rescue from a marketplace. Your attention is being bought by something. Paul commands you to buy it back. The days are evil not simply because they contain suffering but because they contain distraction that consumes appointed opportunity.
Proverbs 4:23 — "Keep thy heart with all diligence; for out of it are the issues of life" — uses the Hebrew word mishmar for "diligence," which means a guard post, a watch. The heart — in Hebrew thought the seat of attention, desire, and decision — is to be guarded as a fortification. What you allow to repeatedly enter the guarded space shapes what flows out of it. Unguarded screen consumption is not merely wasted time; it is a gate left open.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.