What does the word "heis" mean in Mark 12:29 and why is it used instead of "monos"?

In Mark 12:29, the word εἷς (heis) means "one" and conveys the biblical confession of the one God. It is used not as a hidden proof of a particular theological formula, but because Mark records Jesus' words in the Greek form of Deuteronomy; at the same time, this text is fully consistent with the biblical revelation of the Father, the Son, and the Holy Spirit.

When a scribe asked Jesus about the most important commandment, Christ began His answer with the words known to every pious Israelite as the "Shema": "Hear, O Israel." In the Greek text of Mark we read: "Κύριος εἷς ἐστιν", that is, "the Lord is one." The word εἷς is pronounced approximately as "heis" and is the common Greek numeral "one." To understand it correctly, it is important not to read more into a single word than its context allows.

Jesus Quotes the Shema of Israel

Christ's response is a direct quote from the Old Testament. In the Hebrew text of Deuteronomy, the word is אֶחָד (echad): "one." The Greek translators of the Septuagint, which was widely known in apostolic times, translated it with the word εἷς. It is this established biblical phrasing that Mark repeats.

“Hear, O Israel: The LORD our God, the LORD is one!” Deut 6:4

“Jesus answered, ‘The most important is, “Hear, O Israel: The Lord our God, the Lord is one.”’” Mark 12:29

Thus, the primary reason for choosing εἷς is simple: it is the accurate and natural translation of the Hebrew echad in this creedal statement. Christ does not invent a new formulation, but reaffirms the fundamental truth: Israel must worship only the Lord, not the many gods of the nations.

What does εἷς mean, and what does μόνος mean?

The word εἷς means "one" in the sense of number, unity, or uniqueness. It can be used in ordinary counting: one day, one person, one God. In Mark 12:29, the emphasis is on the fact that the Lord is the only God of His people.

The word μόνος (monos) indeed often means "alone," "only," "sole," "by oneself." But we should not contrast these words as if μόνος necessarily means "absolutely isolated" while εἷς automatically means a "composite unity." The meaning of words is determined by sentence structure and context. In the New Testament, μόνος can simply emphasize the uniqueness of God.

“For there is one God, and there is one mediator between God and men, the man Christ Jesus,” 1 Tim 2:5

“to the only God, our Savior, through Jesus Christ our Lord, be glory, majesty, dominion, and authority, before all time and now and forever. Amen.” Jude 1:25

Therefore, εἷς in Mark does not need to be interpreted as a denial of personal distinction within the Godhead. Likewise, μόνος on its own would not be a philosophical claim about the "solitariness" of God. However, in the quotation of the Shema, the natural and traditional word is precisely εἷς.

"Echad" is Not a Technical Word for the Trinity

It is sometimes asserted that echad always denotes a "composite unity," whereas יָחִיד (yachid) supposedly means absolute singularity. This is an oversimplification. Echad is primarily the ordinary word for "one"; it can describe one person, one object, or a unity of multiple individuals, depending on the context. For instance, a husband and wife, remaining two persons, become "one flesh."

“and they shall become one flesh.” Gen 2:24

This passage shows that the word "one" can sometimes describe unity. However, it does not prove that every occurrence of echad contains the idea of plurality. In Deuteronomy 6:4, the main point is not to explain the inner nature of God, but to proclaim His oneness, uniqueness, and exclusive right to His people's faithfulness.

The One God and the Biblical Revelation of the Trinity

The Seventh-day Adventist Church confesses one God in three co-eternal Persons: Father, Son, and Holy Spirit. This doctrine is not built upon the single word εἷς, but flows from the comprehensive testimony of Scripture. The Bible unmistakably proclaims that God is one, and simultaneously calls the Father God, the Son also God, and shows the personal and divine activity of the Holy Spirit.

“Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit,” Matt 28:19

“In the beginning was the Word, and the Word was with God, and the Word was God.” John 1:1

Ellen White also spoke clearly of the "three living persons of the heavenly trio," emphasizing not three gods, but the saving presence of the Father, the Son, and the Holy Spirit in the life of the believer.

Conclusion and Practical Application

The word εἷς in Mark 12:29 means "one" and is used because Mark renders Jesus' words from the Shema in its biblical Greek form. It proclaims the oneness and uniqueness of the Lord, rather than serving as an isolated linguistic proof for or against the Trinity. Practically, this means: worship God with undivided loyalty. Let love for the one Lord direct your thoughts, decisions, family, and service to others.

“You shall love the LORD your God with all your heart and with all your soul and with all your might.” Deut 6:5