Darkness; either,
1. A darkness and confusion of mind so great that thou canst not discern the true cause and use of all thy sufferings. Or,
2. Grievous calamities, which are oft called darkness, which are such that thou canst see no way nor possibility of escaping. Either thou art troubled with fear of further evils, as it is said, Job 21:10, or with the gross darkness of thy present state of misery. Abundance of waters, i.e. plenty and variety of sore afflictions, which are frequently compared to waters, as Psalms 18:16 Psalms 66:12 Isaiah 43:2.