psalms 40:12 For innumerable evils have compassed me about: mine iniquities have taken hold upon me, so that I am not able to look up; they are more than the hairs of mine head: therefore my heart faileth me. - Free Bible Online

      12. evils--inflicted by others.
      iniquities--or penal afflictions, and sometimes calamities in the wide sense. This meaning of the word is very common (Ps 31:11; 38:4; compare Ge 4:13, Cain's punishment; Ge 19:15, that of Sodom; 1Sa 28:10, of the witch of En-dor; also 2Sa 16:12; Job 19:29; Isa 5:18; 53:11). This meaning of the word is also favored by the clause, "taken hold of me," which follows, which can be said appropriately of sufferings, but not of sins (compare Job 27:20; Ps 69:24). Thus, the difficulties in referring this Psalm to Christ, arising from the usual reading of this verse, are removed. Of the terrible afflictions, or sufferings, alluded to and endured for us, compare Lu 22:39-44, and the narrative of the scenes of Calvary.
      my heart faileth me-- (Mt 26:38), "My soul is exceeding sorrowful, even unto death."
      cannot look up--literally, "I cannot see," not denoting the depression of conscious guilt, as Lu 18:13, but exhaustion from suffering, as dimness of eyes (compare Ps 6:7; 13:3; 38:10). The whole context thus sustains the sense assigned to iniquities.

JFB.