Revelation 18:6

The angel further called on God’s enemies whom He will use to pay Babylon back fully for its wicked deeds, pride, and self-indulgent conduct (cf. Revelation 17:16-17; Jeremiah 50:29). This is a call for God’s application of the lex talionis, the law of retaliation (cf. Matthew 7:2; Galatians 6:7-8). To pay back double is a way of saying to pay back fully (cf. Revelation 18:7; Exodus 22:4; Exodus 22:7; Exodus 22:9; Isaiah 40:2; Isaiah 61:7; Jeremiah 16:18; Jeremiah 17:18; Zechariah 9:12). [Note: Hailey, pp. 361-62; Hughes, p. 191; Meredith G. Kline, "Double Trouble," Journal of the Evangelical Theological Society 32:2 (June 1989):171-79.] Babylon had persecuted and murdered the saints (Revelation 18:24; Revelation 19:2). The cup she used to seduce others will become the instrument of her own punishment (cf. Revelation 18:3; Revelation 14:10).

"This is not a prayer for personal vengeance by the persecuted saints, but a heavenly interpretation of the divine response to cruelty committed by wicked persons who have passed the point of no return in their moral choices. The last hour has now struck, and it is too late for repentance. This is a judicial pronouncement against a sinful civilization that has reached the ultimate limit of evil." [Note: Thomas, Revelation 8-22, pp. 322-23. Cf. Kiddle, pp. 366-67; Hughes, p. 190.]