For as (Good News Translation “In the same way that”) is the signal by which verse 40 is made the key to the interpretation of “the sign of the prophet Jonah” of verse 39.

Was three days and three nights in the belly of the whale is taken directly from the Septuagint of Jonah 1.17 (Septuagint, 2.1). For people who have never been introduced to the story of Jonah, it may be necessary to provide a footnote.

Good News Translation renders was as “spent.” Other words are “stayed” or “passed.”

Three days and three nights is not always natural. Some languages say simply “three days” or “three full days.”

So will (Good News Translation “In the same way … so will”) translates a Greek structure which draws an analogy between the three days and nights spent by Jonah in the big fish and the period of time spent by the Son of Man in the heart of the earth. For a discussion of the Son of man, see 8.20. In this chapter he is mentioned in verses 8, 32, and 40; as elsewhere in the New Testament, the reference is to Jesus, and this should be clear in translation.

Good News Translation has conveyed very clearly the meaning of the construction of For as … so will. In other languages the form may be slightly different, as in “For Jonah was … It will be just like that with….” It may even be helpful to repeat the “sign” of verse 39, as in “For the sign to Jonah was that he spent three full days inside the big fish. In the same way, the sign to you will be when the Son of Man spends three days deep in the earth.”

Whale (so also New American Bible) is the traditional rendering of the Greek word used here. Good News Translation has “big fish”; the most accurate term is perhaps “sea monster” (Barclay, New Jerusalem Bible, New English Bible, Die Bibel im heutigen Deutsch). The major problem with “sea monster” is that some readers may assume that this represents an attempt to make the Jonah story into a fairy tale. For this reason it is probably best to use a more neutral term such as “big fish” or “very big fish.”

As for belly, some translators will say “stomach,” but others will find it sufficient to say “inside.”

Heart of the earth represents a literal translation of the Hebrew idiom used by Matthew. It is perpetuated by most translations, but New English Bible has “bowels of the earth,” and Good News Translation “depths of the earth.” The place referred to is the grave rather than the world of the dead. Accordingly, one may render “deep in the earth,” “deep in the ground,” or possibly “buried in the ground.”

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 .