Psalms 137:3
For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion. For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion.
In the setting of the verse, captive Israel hung their harps on the willows while those who had carried them away demanded mirth and the songs of Zion. Those songs of Zion can be sung again when pride and selfishness are turned from to missionary love and service. The present is the time to sing them as a living testimony of victories won through earnest prayer and personal spiritual struggle.
They can be sung when temptation comes and used as a weapon against discouragement. They can be sung to encourage oneself and others, strengthening hope and turning darkness to light. Sung in this way, the song becomes an expression of comfort and praise as God's promises brighten the journey toward heaven.