Why did the Israelites refuse to sing about Zion? (Psalm 137:4)

Psalm 137 New International Version (NIV)
Psalm 137
1 By the rivers of Babylon we sat and wept
    when we remembered Zion.
2 There on the poplars
    we hung our harps,
3 for there our captors asked us for songs,
    our tormentors demanded songs of joy;
    they said, “Sing us one of the songs of Zion!”

4 How can we sing the songs of the Lord
    while in a foreign land?

Psalms 137:1 - 4

ESV - ¹ By the waters of Babylon, there we sat down and wept, when we remembered Zion. ² On the willows there we hung up our lyres.

Clarify • Share • Report • Asked March 09 2019 • Jack Gutknecht