'Feebleness' in the Bible

From the end of the land unto Thee I call, In the feebleness of my heart, Into a rock higher than I Thou dost lead me.

May their eyes be dimmed so that they cannot see,And make their loins shake continually [in terror and weakness].

At the noise of the stamping of the hoofs of his strong horses, at the rushing of his chariots, and at the rumbling of his wheels, the fathers shall not look back to their children for feebleness of hands;

In the feebleness within me of my soul Jehovah I have remembered, And come in unto Thee doth my prayer, Unto Thy holy temple.