And Jesus answered him, The first of all the commandments is, Hear, O Israel; The Lord our God is one Lord:
Mark 12:29
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 Jesus answered him, The first of all the commandments is, Hear, O Israel; The Lord our God is one Lord:
30 And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment.
31 And the second is like, namely this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these.
32 And the scribe said unto him, Well, Master, thou hast said the truth: for there is one God; and there is none other but he:
33 And to love him with all the heart, and with all the understanding, and with all the soul, and with all the strength, and to love his neighbour as himself, is more than all whole burnt offerings and sacrifices.
Mark 12:28-33
The above Bible verses show Jesus explain to his disciples that the first and most important commandment is to worship God, the Creator.