to live, whether literally or figuratively; causatively, to revive
me after thy lovingkindness
kindness; by implication (towards God) piety: rarely (by opposition) reproof, or (subject.) beauty
so shall I keep
to hedge about (as with thorns), i.e. guard; generally, to protect, attend to, etc.
testimony -- testimony, witness.
of thy mouth
the mouth (as the means of blowing), whether literal or figurative (particularly speech); specifically edge, portion or side; adverbially (with preposition) according to