It would seem to me that if Jesus gave us a great and first commandment, we would want to be on top of that. Indeed, he did. (It surprises me how many Christians are unaware of this.):
[34] But when the Pharisees heard that he had silenced the Sad'ducees, they came 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.
[38] This is the great and first commandment. Matt 22:34-38 RSV
Absolutely and Jesus was quoting the Word/scriptures from the Old Testament. I believe Jesus is the author of Torah (Moses took dictation...so to speak).
(Deu 4:29) But if from thence thou shalt
seek the LORD thy God, thou shalt find him, if thou
seek him with all thy heart and with all thy soul.
(Deu 6:5) And thou shalt
love the LORD thy God with all thine heart, and with all thy soul, and with all thy might.
(Deu 10:12) And now, Israel, what doth the LORD thy God require of thee, but to
fear the LORD thy God, to
walk in all his ways, and to
love him, and to
serve the LORD thy God with all thy heart and with all thy soul,
(Deu 26:16) This day the LORD thy God hath commanded thee to do these statutes and judgments:
thou shalt therefore keep and do them with all thine heart, and with all thy soul.
(Deu 30:2) And shalt
return unto the LORD thy God, and shalt
obey his voice according to all that I command thee this day, thou and thy children, with all thine heart, and with all thy soul;
(Deu 30:6) And the LORD thy God will circumcise thine heart, and the heart of thy seed,
to love the LORD thy God with all thine heart, and with all thy soul, that thou mayest live.
(Deu 30:10) If thou shalt
hearken unto the voice of the LORD thy God, to
keep his commandments and his statutes which are written in this book of the law, and
if thou turn unto the LORD thy God with all thine heart, and with all thy soul.
Of course, the lawyer in Matthew knew the scriptures well and probably had the whole Torah memorized. Jesus also knew the scriptures, after all, He is the author of the Word and can quote His own words.