What does Psalm 137:7 mean?
Jacob was the patriarch of the nation of Israel (Genesis 32:28; 35:23–26). His twin brother was Esau (Genesis 25:24–26), patriarch of the nation of Edom (Genesis 25:30; 36:1, 8). When Babylon attacked Jerusalem (2 Chronicles 36:17–21), Edom did not merely stand by (Obadiah 1:10–11). They apparently helped the Babylonians capture Jews fleeing the carnage (Obadiah 1:13–14) and participated in sacking Jerusalem. Catastrophes are often referred to as "the day" in Scripture (Isaiah 9:4; Ezekiel 13:5; Joel 2:1; 2 Thessalonians 2:2; 2 Peter 3:12).Other Old Testament passages predict the Lord's judgment on Edom (Obadiah 1:1–4, 18; Ezekiel 25:12–14). Because of what the Edomites did during Jerusalem's destruction, the psalmist prays for divine vengeance (Obadiah 1:15). This idea of an enemy receiving the very evils they have done continues in the next verses (Psalm 137:8–9).
Psalm 137:7–9 contains a bitter, intense prayer for vengeance. When Israel was captured by Babylon (2 Chronicles 36:17–21) they were subject to horrific slaughter. This included violence against even children (2 Kings 8:12; Isaiah 13:16; Hosea 10:14). Rather than giving shelter, the Edomites apparently helped Babylon capture fleeing Jews (Obadiah 1:10–11, 14). The psalmist's wish is for Babylon to experience the same horrors, including the gruesome murder of their infants.
After being captured by Babylon (2 Chronicles 36:17–21), the people of Israel are teased by their new masters. The Babylonians ask the Jews to perform songs from their homeland. But the Israelites cannot bring themselves to sing. They vow to remember what happened to their city and their people. The psalmist prays that God would bring harsh vengeance on Edom and Babylon. He hopes they suffer the same gruesome evils which they inflicted upon Israel.