Faced with an enemy of overwhelming military might and enduring a long, crushing subjugation, the Israelites are driven to a place of profound despair. Left with no other options, they pour out their hearts in prayer. This outpouring of emotion is not a standard plea; it is an exceptionally great and powerful cry, far more intense than their prayers in previous times [מלבי״ם].
The sheer intensity of this cry to God stems from three overwhelming factors. First, the enemy holds an absolute military advantage, possessing nine hundred chariots as strong as iron [מצודת ציון, ביאור שטיינזלץ]. Facing such a force, the Israelites have no natural chance of victory. Stripped of the courage to even attempt a battle, their only remaining recourse is to cry out to Him in prayer [מצודת דוד, מלבי״ם].
Second, the nature of their oppression is deeply severe. The enemy exerts a forceful pressure that crushes them daily. While this involves intense physical abuse and subjugation [מצודת דוד], the suffering extends into the mental and spiritual realms. The hardship is magnified as the enemy constantly hurls harsh insults and blasphemies at them [רש״י, מלבי״ם].
Finally, the deep despair that fuels their cry is compounded by the sheer length of their hardship. For twenty continuous years, the Israelites have suffered under this heavy yoke [מלבי״ם].