Revised Standard Version retains the formal structure of the Greek text, which continues in this verse the sentence begun in verse 17. Translators can also begin a new sentence, as in “Do that so that people won’t notice that you are fasting” or “You should do this so no one will know when you are fasting.”

Who is in secret … who sees in secret: the Greek noun used here for secret differs from that of verses 4 and 6. But there is no difficulty in interpreting the two nouns as synonymous. Problematic, however, is how God may be spoken of as the one who is in secret. Good News Translation resolves the problem by translating “who is unseen.” This interpretation finds support in the Septuagint of Jeremiah 23.24. The same phrase is used there (except in the plural), where the text reads, “Can anyone hide himself in secret places where I cannot see him?” In the Jeremiah passage the phrase is easily equivalent to “in places where he cannot be seen” or “in places where he is unseen.” New American Bible translates the two clauses as “who is hidden … who sees what is hidden,” and New Jerusalem Bible translates the two of them “who sees all that is done in secret.” New English Bible has “your Father who is in the secret place … your Father who sees what is secret.”

Translators most often do something similar to what they did in verses 4 and 6. They can say “Your Father who is in that private place will see (or, know about) your fasting, and he will reward you” or “Your Father whom men (or, you) can’t see will see what you do and will reward you.” Few translators will find it natural to repeat the phrase in secret, although Good News Translation has done it in English. Those who do will render the verse “So that no one will know when you are fasting except your Father whom no one can see. He sees all that is done in private, and will reward you.”

Father, as in 5.16, is God.

Will reward you: see comments on 5.12 and 6.4, where the same expression is used.

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .