Job 4:4 New English Translation

⁴Your words have supported^[a] those
who stumbled,^[b]
and you have strengthened the knees
that gave way.^[c]

Job 4:4 tn Both verbs in this line are imperfects, and probably carry the same nuance as the last verb in v. 3, namely, either customary imperfect or preterite. The customary has the aspect of stressing that this was what Job used to do.
Job 4:4 tn The form is the singular active participle, interpreted here collectively. The verb is used of knees that give way (Isa 35:3; Ps 109:24).
Job 4:4 tn The expression is often translated as “feeble knees,” but it literally says “the bowing [or “tottering”] knees.” The figure is one who may be under a heavy load whose knees begin to shake and buckle (see also Heb 12:12).sn Job had been successful at helping others not be crushed by the weight of trouble and misfortune. It is easier to help others than to preserve a proper perspective when one’s self is afflicted (E. Dhorme, Job, 44).

New English Translation (NET)