luke 18:13 And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner. - Free Bible Online

      13. standing afar off--as unworthy to draw near; but that was the way to get near (Ps 34:18; Isa 57:15).
      would not lift up--blushing and ashamed to do so (Ezr 9:6).
      smote, &c.--kept smiting; for anguish (Lu 23:48), and self-reproach (Jer 31:19).
      be merciful--"be propitiated," a very unusual word in such a sense, only once else used in the New Testament, in the sense of "making reconciliation" by sacrifice (Heb 2:17). There may therefore, be some allusion to this here, though not likely.
      a sinner--literally, "the sinner"; that is, "If ever there was one, I am he."

JFB.