The phrases "kingdom of God" (ἡ βασιλεία τοῦ θεοῦ) and "kingdom of Heaven" (ἡ βασιλεία τῶν οὐρανῶν) occur eighty-six (86) times in the gospels.
The phrase "kingdom of Heaven" occurs thirty-two (32) times and only in the Gospel of Matthew. The phrase "kingdom of God" occurs thirty-two (32) times in the Gospel of Luke, the most of any book in the Bible.
An examination of Synoptic parallels will demonstrate that the two phrases refer to the same idea.
"the kingdom of Heaven is at hand" (Matt. 4:17) || "the kingdom of God is at hand" (Mark 1:15)
"Blessed are the poor in spirit, for theirs is the kingdom of Heaven" (Matt. 5:3) || "Blessed are the poor, for yours is the kingdom of God (Luke 6:20)
"Among those born of women there has not risen a greater than John the Baptist, notwithstanding he who is least in the kingdom of Heaven is greater than him." (Matt. 11:11) || "Among those born of women there is not a greater prophet than John the Baptist, but he who is least in the kingdom of God is greater than him." (Luke 7:28)
"the mysteries of the kingdom of heaven" (Matt. 13:11) || "the mysteries of the kingdom of God" (Mark 4:11 cp. Luke 8:10)
"the kingdom of Heaven is like a grain of mustard seed (Matt 13:31) || "the kingdom of God...is like a grain of mustard seed" (Mark 4:30-31 cp. Luke 13:18-19)
"The kingdom of Heaven is like leaven" (Matt. 13:33) || "the kingdom of God...is like leaven" (Luke 13:20)
"Except you be converted, and become as little children, you shall not enter into the kingdom of Heaven" (Matt. 18:3-4) || Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein" (Mark 10:15)
"Allow little children, and do not forbid them to come to me, for of such is the kingdom of Heaven." (Matt. 19:14) || "Allow the little children to come to me, and do not forbid them, for of such is the kingdom of God." (Mark 10:14 cp. Luke 18:16)
"a rich man shall hardly enter into the kingdom of Heaven" (Matt. 19:23) || "How hardly shall they who have riches enter into the kingdom of God!" (Luke 18:24)
In other words, "kingdom of God" = "kingdom of Heaven." If this is so, then "God" = "Heaven," which leads us into my next point.
The reason why Matthew uses the phrase "kingdom of Heaven" more often than "kingdom of God" (which he uses only five (5) times in his gospel, although there are textual variants) is because he wrote to a Jewish audience, and the Jews did not pronounce the Tetragrammaton יהוה (Yahveh), and sometimes not even the word אֱלֹהִים (elohim). For example, today, Jews do not say אֱלֹהִים (elohim), but rather, אֱלֹקִים (elokim), and certainly never the Tetragrammaton. Rather than pronouncing those, they used "substitutes." Some of these substitutes include:
- מָקוֹם (makom), i.e. "Place"
Jastrow, p. 830, on Hebrew מָקוֹם:
- גְּבוּרָה (gevurah), i.e. "Power"
Jastrow, p. 205, on Hebrew גְּבוּרָה:
- שָׁמַיִם (shamayim), i.e. "Heaven"
Jastrow, p. 1595, on Hebrew שָׁמַיִם:
Jastrow, p. 1595, on Aramaic שְׁמַיָּא:
The Hebrew word שָׁמַיִם (shamayim), which is translated into English as "heaven," is used on certain occasions as a כִּנּוּי (kinnui), or a "substitute," "nickname."
When the prophet Daniel (Dan. 4:26) wrote שַׁלִּטִן שְׁמַיָּא, it doesn't mean that "the heavens rule," but that "Heaven rules," for the Aramaic שְׁמַיָּא, like the Hebrew שָׁמַיִם, was used by Daniel as a substitute for the Tetragrammaton. Thus, there is evidence that this practice began in the Babylonian captivity, long before the 1st century A.D.
On the Greek word οὐρανός, the equivalent of the Hebrew word שָׁמַיִם, Joseph Henry Thayer wrote (p. 466),
in particular for God (Dan. 4:23, and often by the Rabbins, influenced by an over-scrupulous reverence for the names of God himself; cf. Schürer in the Jahrbb. f. protest. Theol., 1876, p. 178 sq.; [Keil, as below]): ἁμαρτάνειν εἰς τὸν οὐρ., Lk. 15:18, 21; ἐκ τοῦ οὐρ., i. q. by God, Jn. 3:27; ἐξ οὐρ., of divine authority, Mt. 21:25; Mk. 11:30; Lk. 20:4; ἐγαντίον τοῦ οὐρανοῦ, 1 Macc. 3:18 (where the τοῦ θεοῦ before τοῦ οὐρ. seems questionable); ἐκ τοῦ οὐρ. ἡ ἰσχύς, ib. 19; ἡ ἐξ οὐρ. βοήθεια, 12:15; 16:3, cf. 3:50–53, 59; 4:10, 24, 30, 40, 55; 5:31; 7:37, 41; 9:46;
In his commentary on Matt. 3:2, John Lightfoot (pp. 48-49) wrote,
In the King James Version, 1769 edition, the phrase "kingdom of God" occurs five (5) times in the Gospel of Matthew:
On Matt. 6:33, Constantin Tischendorf noted,
There are many witnesses that lack τοῦ θεοῦ and instead have τῶν οὐρανῶν, including Justin Martyr (2nd c. A.D.) in his Apology on behalf of Christians to Antoninus Pius (a.k.a. First Apology):
But seek the kingdom of Heaven, and all these things shall be added to you.
ζητεῖτε δὲ τὴν βασιλείαν τῶν οὐρανῶν, καὶ ταῦτα πάντα προστεθήσεται ὑμῖν.
On Matt. 19:24, Constantin Tischendorf noted,
Again, he notes many witnesses which have τῶν οὐρανῶν (or its Latin equivalent) rather than τοῦ θεοῦ, including the Vulgate, Clement of Rome, Origen, Eusebius, Jerome, and Augustine.
There are no relevant textual variants on Matt 12:28, 21:31, or 21:43, but that does not mean the original manuscript did not have τῶν οὐρανῶν rather than τοῦ θεοῦ. It only means that we've not found any manuscripts that contain it, and we may never will. It's evident that the "kingdom of Heaven" phrases in Matthew's gospel match the "kingdom of God" phrases in the other Synoptics. Personally, I don't think any of the occurrences of "kingdom of God" in Matthew's gospel are legitimate; I believe they eventually crept into the text through amendations from scribes who were not familiar with the circumlocution. More importantly, the two phrases are identical, and it's a fact that the Jewish people spoke or wrote the word "Heaven" (it's Hebrew or Greek equivalent) as a circumlocution for the Tetragrammaton or other words specifically referring to God (i.e., like the word "God" itself).
Lightfoot, John. Horae Hebraicae et Talmudicae (Hebrew and Talmudical Exercitations), Vol. 2. Trans. Gandell, Robert. Oxford: UP of Oxford, 1859.
Jastrow, Marcus. A Dictionary of the Targumim, the Talmud Babli and Yerushalmi, and the Midrashic Literature. London: Luzac; New York: Putnam, 1903.
Thayer, Joseph Henry. A Greek-English Lexicon of the New Testament: Being Grimm Wilke’s Clavis Novi Testamenti. New York: American Book, 1889.
Tischendorf, Constantin. Novum Testamentum Graece, Vol. 1. Lipsiae: Giesecke & Devrient, 1869.