Albert Barnes' Notes on the Whole Bible - Matthew 6:17-18
But thou when thou fastest, anoint ... - That is, appear as you do daily. Do not assume any new appearance, or change your visage or dress. The Jews and all neighboring nations were much in the habit of washing and anointing their bodies. This washing was performed at every meal; and where it could be effected, the head, or other parts of the body, was daily anointed with sweet or olive oil. In a warm climate, exposed to the great heat of the sun, this practice conduced much to health,... read more
The Pulpit Commentary - Matthew 6:18
Which is in secret ( τῷ ἐν τῷ κρυφαίῳ ); Matthew 6:6 , note. Shall reward thee openly ( Matthew 6:4 , note). read more