The publican, standing afar off. — The words point to a sense of shame which kept the publican away from the crowd of worshippers who pressed forward to the ark-end of the outer court of the Temple — away, above all, from the devout and respectable Pharisee. So might some “forlorn and desperate castaway” crouch, at some solemn service, in the remote corner of the nave of a cathedral. He, too, stood, for that was the received attitude of prayer, and kneeling, at such a time and in that place, would have been ostentatious.
Would not lift up so much as his eyes unto heaven. — There is a subtle delineation of what one may call the physiognomy of repentance, which should not pass unnoticed. The downcast look stands in contrast with the supercilious expression (taking the adjective in its most literal sense) of the Pharisee.
But smote upon his breast. — The same act meets us as the expression of extremest sorrow in those who stood by the cross (Luke 23:48). Looked at physiologically, it seems to imply a tension of the vessels of the heart, such as we all feel in deep emotion, to which outward impact seems, in some measure, to minister relief. So men strike their chest, when suffering from cold, to quicken the circulation of the blood. As being spontaneous and involuntary, it attested the reality of the emotion, and contrasted with the calm, fixed attitude of the Pharisee.
God be merciful to me a sinner. — Literally, to me the sinner, as though, like St. Paul, he singled out his own guilt as exceptional, and thought of himself as “the chief of sinners” (1 Timothy 1:15).