Psalms - Chapter 13
Speaking of exiles in his future (but in our past), David asks G-d how long He will conceal Himself from us. How long must we seek to evade worries and despair? How long will our enemies be permitted to dominate us? David calls to G-d and asks Him to answer, providing light to dispel the darkness; to do otherwise may result in our demise.
If G-d does not answer us, the enemy may ultimately boast that they have conquered us and they will rejoice in our downfall. We place our trust in G-d's mercy and kindness and we will praise Him for His salvation.