These scriptures were an embedded part of Jewish life in the first century, as they still are today. They basically describe the Torah observant Jew and what is expected of him. To make reference to this group of scriptures, you need only say the first word,
שמע (shema), and it is understood what you are referencing.
When Yeshua was asked what the greatest commandment was, however, he went much further than to give the first word. He left no doubt as to what he was saying.
Mark 12:28
28 And one of the scribes came, and having heard them reasoning together, and perceiving that he had answered them well, asked him, Which is the first commandment of all?
29 And Yeshua answered him, The first of all the commandments is,
שמע ישראל יהוה אלהינו יהוה אחד
(Shema Yisrael ADONAI elohenu ADONAI echad.)
Hear, O Israel; the LORD our God, the LORD is One:
30 And you shall love the Lord your God with all your heart, with all your soul, and with all your mind, and with all your strength: this is the first commandment.
31 And the second is like this, You shall love your neighbor as yourself.
Here Yeshua is quoting two passages from the Torah;
Deuteronomy 6:4 and Leviticus 19:18. By doing so he expresses the major profession of Jewish faith and emphasizes monotheism as the first priority of belief. He also supports the most basic passage in Jewish liturgy.