Psalms 143:3

For the enemy hath persecuted my soul - Has persecuted me; has sought my life.

He hath smitten my life down to the ground - He has, as it were, trampled me down to the earth. The word rendered “smitten” means to break in pieces, to beat small, to crush. See Psalms 72:4; Psalms 89:10; Job 6:9. His very life seemed to be crushed out as one that is trodden down to the ground.

He hath made me to dwell in darkness - He has made my life like that of one who dwells in darkness; he has made it a life of sorrow, so that I have no comfort - no light.

As those that have been long dead - A similar expression occurs in Lamentations 3:6 : “He hath set me in dark places, as they that be dead of old.” The same Hebrew words are used. The word rendered “long” means, age, duration, eternity: Psalms 139:24. The idea here is, that his condition was like that of those who had been long in their graves; who had long since ceased to see any light; whose abode was utter and absolute gloom.