'Failing' in the Bible

'And among those nations thou dost not rest, yea, there is no resting-place for the sole of thy foot, and Jehovah hath given to thee there a trembling heart, and failing of eyes, and grief of soul;

Why hath my pain been perpetual? And my wound incurable? It hath refused to be healed, Thou art surely to me as a failing stream, Waters not stedfast.