The Command in Deuteronomy
You shall love the LORD your God with all your heart and with all your soul and with all your might. (Deuteronomy 6:5) [ESV]
ואהבת את יהוה אלהיך בכל־לבבך ובכל־נפשך ובכל־מאדך
Might is מְאֹד which does mean strength. However, that is not how this command was taught:
Might: Hebrew "me'od" is elsewhere an adverb meaning "very" or "exceedingly." It is used as a noun only here and in the Deuteronomistic description of King Josiah, which cites this verse to portray Josiah as the paragon of obedience to Torah (2 Kings 23.25). While the word's basic meaning is "might" or "strength," it was understood as "wealth" or "property" both at Qumran (CD 9.11; 12.10) and in early rabbinic literature (Tg. Jon.; Sifre). The two interpretations each call for full commitment to God, whether psychological or practical; both are preserved in the Mishnah (m. Ber. 9.5)1
A literal translation might be "to love God with all 'your everything.'" "Strength" by itself is deficient, at least in terms of the rabbinic interpretation and instruction. So, not ...with all your strength but "...with the "results of all your strength," (such as your wealth and property).
Similarly, the command "to love" is understood as requiring action:
The paradox of commanding a feeling (as in Leviticus 19.17-18) is resolved with the recognition that covenantal "love" does not refer to internal sentiment or to private emotion. The focus is, instead, upon loyalty of action toward both deity and neighbor...2
Therefore, quoting verbatim would fail to convey how one was taught to apply the command.
The Command in Luke
First, in Luke, it is not Jesus who is speaking:
25 And behold, a lawyer stood up to put him to the test, saying, “Teacher, what shall I do to inherit eternal life?” 26 He said to him, “What is written in the Law? How do you read it?” 27 And he answered, “You shall love the Lord your God with all your heart and with all your soul and with all your strength (ἰσχύϊ) and with all your mind (διανοίας), and your neighbor as yourself.” (Luke 10)
"He" who is citing the command is a νομικός, an instructor or interpreter of the Mosaic law. Second, the lawyer is not quoting directly from the Greek translation (LXX):
And thou shalt love the Lord thy God with all thy mind, and with all thy soul, and all thy strength. (LXX-Deuteronomy 6:5)
καὶ ἀγαπήσεις κύριον τὸν θεόν σου ἐξ ὅλης τῆς καρδίας σου καὶ ἐξ ὅλης τῆς ψυχῆς σου καὶ ἐξ ὅλης τῆς δυνάμεώς σου
Where the LXX treats the Hebrew מְאֹד as "strength" using δύναμις which is physical ability, the lawyer uses ἰσχύς which means "capability to function effectively, strength, power, might."3
For example:
saying with a loud voice, “Worthy is the Lamb who was slain,
to receive power and wealth and wisdom and might (ἰσχὺν)
and honor and glory and blessing!” (Revelation 5:12)
In fact, some translations have "strength." The lawyer has made two changes to the literal command. First, he rejected the LXX use of δύναμις which more properly means "physical ability" and used ἰσχύς which means the type of "strength" more in keeping with how one is taught to apply the command. Second, he added "mind" (διανοίας), which means understanding or way of thinking.
Obviously, Jesus approved the lawyer's interpretation of Deuteronomy 6:5 (cf. Luke 10:28) and his decision to include the command in Leviticus (19:18).
The Command in Matthew
In Matthew, the roles are reversed and Jesus was questioned by a lawyer (νομικός):
34 But when the Pharisees heard that he had silenced the Sadducees, they gathered together. 35 And one of them, a lawyer, asked him a question to test him. 36 “Teacher, which is the great commandment in the Law?” 37 And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind (διανοίᾳ). 38 This is the great and first commandment. 39 And a second is like it: You shall love your neighbor as yourself.
(Matthew 22)
His answer is very similar to the one given by the lawyer. The only significant difference is, Jesus does not include strength (ἰσχύϊ):
Love the LORD your God with all your:
The Law, Deuteronomy: heart - soul - might
The Lawyer (Luke): heart - soul - might - mind
Jesus (Matthew): heart - soul - mind
From the point of a literal translation of the Law, Jesus replaced "might" in Deuteronomy with "mind." From the standpoint of how the lawyer interpreted or taught the Law, Jesus omitted "might" altogether. Technically, "might" is expected based on the Hebrew text. However, when "love" is understood as an action not an inward feeling, "might" is largely unnecessary and, "might" alone falls short, as the lawyer's addition shows.
"Mind" which is added by both Jesus and the lawyer is διάνοια which has five uses:
❶ the faculty of thinking, comprehending, and reasoning. understanding, intelligence, mind
❷ mind as a mode of thinking, disposition, thoughts, mind
❸ mind focused on objective, purpose, plan
❹ mind as fantasizing power, imagination
❺ mind in sensory aspect, power, impulse
The first is likely the meaning in both Luke and Matthew (also Mark 12:30).4
Yet, like love, there is a sense implying purposeful or focused action.
The Command in Mark
In yet another test, Jesus gives another answer:
28 And one of the scribes came up and heard them disputing with one another, and seeing that he answered them well, asked him, “Which commandment is the most important of all?” 29 Jesus answered, “The most important is, ‘Hear, O Israel: The Lord our God, the Lord is one. 30 And you shall love the Lord your God with all your heart and with all your soul and with all your mind and with all your strength.’ 31 The second is this: ‘You shall love your neighbor as yourself.’ There is no other commandment greater than these.” 32 And the scribe said to him, “You are right, Teacher. You have truly said that he is one, and there is no other besides him. 33 And to love him with all the heart and with all the understanding and with all the strength, and to love one's neighbor as oneself, is much more than all whole burnt offerings and sacrifices.” (Mark 12)
After beginning with Deuteronomy 6:4, Jesus gives an answer which includes the four things the lawyer cited:
Love the LORD your God with all your:
The Law (Deuteronomy): heart - soul - might
The Lawyer (Luke): heart - soul - might - mind
Jesus (Matthew): heart - soul - mind
Jesus (Mark): heart - soul - mind - might
The four are the same as in Luke, except Jesus alters the lawyer's sequence by placing mind before might. So what is implied in Matthew is made explicit in Mark: the mind focused on God is seen in all your "might." What is interesting is the scribes response. Like the lawyer in Luke, the scribe acknowledges the accuracy of how Jesus answered, but he paraphrases Jesus' answer. Rather than διάνοια, "mind" which both Jesus and the lawyer used, the scribe calls for a different type of understanding, σύνεσις. The primary difference is σύνεσις is intellectual:5
❶ the faculty of comprehension, intelligence, acuteness, shrewdness
❷ the content of understanding or comprehension, insight, understanding
In terms of the original command the scribe inserted σύνεσις between heart and soul:
Jesus (Mark): heart - soul - mind - might
Scribe (Mark): heart - understanding - soul - might
The Law (Deuteronomy) heart - soul - - might
In contrast to the lawyer whose addition better expressed the intent of the original command, the scribe's paraphrase arguably adds something which is foreign: intellectual understanding. In other words, where both Jesus and the lawyer agree "mind" (διανοίας) is appropriate, the scribe disagrees calling instead for "understanding" (σύνεσις).
A scribe was more than someone who copied texts:
During the time of Christ the scribes exerted a powerful religious influence as teachers, and because of their ability to make judicial decisions based on scriptural exegesis, occupied important positions in the Sanhedrin (Mt 16:21; 26:3).6
The scribe is described as approaching Jesus immediately after the Sanhedrin; given the close relationship with the Sanhedrin, the scribe's paraphrase may display a lack of understanding of the Scripture. σύνεσις is "from συνίημι, to send or bring together. Hence συνίημι is a union or bringing together of the mind with an object..."7
Arguably the scribe's interpretation minimizes the sense of "soul" by adding intellectual "understanding" between heart and soul. Regardless of the intention, mere "intellectual" understanding is foreign to both the literal text and its proper application.
Conclusion
A comparison of Deuteronomy 6:5 shows that Jesus never cited the literal text, as it was originally stated in the LXX. However, as seen in Luke, Jesus was agreeing with how the lawyer taught the command. More importantly, when love is understood as "loyalty of action" to God, "might" is superfluous and if one is to choose only one between might and mind, ἰσχύς is the better way to express the command in Greek.
1 Bernard M. Levinson, The Jewish Study Bible, Edited by Adele Berlin and Marc Zvi Brettler, Oxford University Press, 2004, p.380
2 Ibid.
3 Fredrick William Danker, A Greek-English Lexicon of the New Testament and Other Early Christian Literature, The University Chicago Press, 2000, p. 484
4 Ibid., p. 234
5 Ibid., p. 970
6 Earl B. Robinson, Wycliffe Bible Dictionary, Charles F. Pfeiffer, Howard F. Vos, John Rea, Editors, Hendrickson Publisher, Inc., 2001, p. 1536
7 Vincent Word Studies Mark 12:33