Jesus shows here His divine authority:
In fact, the keeping of Sabbath was a commandment for humans as slaves/servants of God, and even the law-giver Moses was such a slave/servant (Hebrews 3:5), to say nothing about the people he guided in the desert; and the significance of giving of Law and the commandment of Sabbath observance, was that the earthly and crude, materialistic and coarse minds of those servants not to be totally forgetful of God and at least one day per week they should by a compulsory not-working remember their Creator.
But when Jesus came from the Heavens, from the Father, the Logos incarnate, He as the Only-Begotten Son of the Father, as God born from God, enjoying fully the sovereignty of the Father* (*see footnote bellow), He Himself is not under Law, but the One who has given Law to Moses-the-lawgiver for that particular condition of Jewish nation, and thus Himself as the establisher of the Law is not a subject to it, but the Master of or over it. Thus, He authoritatively abolishes the Law (Luke 16:16) opening the gate of His and Father's Kingdom for humans, intimating thus, that this gate was shut during the Law-abiding period of Israel.
Moreover, He wants also us, humans to partake of His divine authority and freedom and make us also not slaves, but sons of God by adoption through Him, the natural and the Only-Begotten, i.e. the Uncreated Son, change our status in face of Creator, investing us, derivatively from Him and not naturally, with the divine qualities (cf. Romans 8:17). Thus, in Jesus Christ we can break all laws, as Augustine beautifully says: "diligere et quod vis fac" - "love [in Holy Spirit] and do whatsoever you wish". Thus, personal conscience immersed in Holy Spirit (Rom 1:9) is the sole guide of a free Christian, for where is the Spirit of Sonship, there is also this blessed freedom (2 Cor.3:17); and such a man has become in Jesus Christ, and in the Spirit that He asked Father to send to his followers, a son of God, and for such there is no Law (Gal 5:23). Will anybody blame a genius writer for not obeying a letter of grammar, if this disobedience was for conveying some intentional nuance of thought that made the writer's point much clearer, impressive and captivating? Of course not! - for the slave-grammarians later will include also this disobedience as a certain grammatical rule. Something similar is also here: the Holy and Vivifying Spirit does not regard the letter of Law, which kills (2 Cor. 3:6), thus a person worshiping God in Spirit and Truth (John 4:23) is free from all idolatrous rigidities, ("political correctness" can also, and does frequently turn into such an idol and and other modern day human-created idiocies). Jesus, thus separates His followers - the children of God - from yet slaves (Matthew 17:25-26), wishing of course that all humanity to become children of God and His co-heirs (1 Tim. 2:4).
Thus, to answer the question: of course, He affirms by this that He is the one who gave to Moses the Law, and as the One who established the Law, Himself is not under its authority, but rather He has authority over the Law, just as the Father does, for the entire authority and sovereignty of Father eternally and naturally (the two - i.e. eternally and naturally - being tautologous as a matter of fact) belongs to the Son also, who is the Lord and God (John 20:28).
(*the very term "Son" metaphorically implies that, for in earthly kingdoms king leaves the entirety of the kingdom to the son, not grudging anything for himself, so that the son's kingdom is the very same as the father's; but in supra-spacial and supra-temporal dimension the Fatherhood-Sonship is to be taken as the eternal birth of the Son from the Father and eternal giving on the part of the Father of everything He has, His entire being, to the Son, so that the Father and the Son have one being eternally, and the Son inherits the entirety of the Father's riches naturally and eternally, without any hiatus or intrusion of time as in earthly kingdoms).