Read Psalms 137:1-4  This is a sad Psalm.  When things were going good, the nation of Israel would forget God.  They would forget that it was really God who was the One who was making things to go good for them.  So God would send preachers called prophets to warn Israel, but sometimes they wouldn’t even listen to the prophets.  God would have to send in one of Israel’s enemies to teach them a lesson.  Once, God sent in King Nebuchadnezzar the king of Babylon who destroyed their country and carried many of the people off to Babylon.  As you could imagine, they were sad to be in a strange country as prisoners of war.  Our verses tell their sad story.  They sat down in a strange place and cried and cried as they remembered their home.  They didn’t feel like singing so they hung their musical harps up on a willow tree.  But to make things worse, the men who had captured them made them to sing songs for their entertainment!  Here they were, in a strange country, sad and away from home, having to sing happy songs.  But deep down in their hearts they longed to be at home in Israel and to be free.  I think that is when they realized what they had done.  That was when they were sorry that they had forgotten God and had neglected God’s words.  I imagine that they were truly sorry for their sins.  But do you know what – God was sorry too.  God didn’t want to punish them, but He had to so that they would see that they were wrong and would come back to Him.  Sometimes God must punish us – for our own good – so that we will learn and come back to where we belong: back to God.