Why would it contradict? He called all of them commandments, which was what you asked about.
Let’s quote it.
Matthew 5:
19 Whoever therefore breaks one of the least of these commandments, and teaches men so, shall be called least in the kingdom of heaven; but whoever does and teaches them, he shall be called great in the kingdom of heaven.
20 For I say to you, that unless your righteousness exceeds the righteousness of the scribes and Pharisees, you will by no means enter the kingdom of heaven.
Which commandments is Jesus referring to? The Ten Commandments He quotes from them verbatim and note, He says not to break the least of the commandment(s) despite the opposite of what many others teach.
21 "
You have heard that it was said to those of old, 'You shall not murder, and whoever murders will be in danger of the judgment.'
22 But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, 'Raca!' shall be in danger of the council. But whoever says, 'You fool!' shall be in danger of hell fire.
23 Therefore if you bring your gift to the altar, and there remember that your brother has something against you,
24 leave your gift there before the altar, and go your way. First be reconciled to your brother, and then come and offer your gift.
25 Agree with your adversary quickly, while you are on the way with him, lest your adversary deliver you to the judge, the judge hand you over to the officer, and you be thrown into prison.
26 Assuredly, I say to you, you will by no means get out of there till you have paid the last penny.
27 "
You have heard that it was said to those of old, 'You shall not commit adultery.'
28 But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart.
29 If your right eye causes you to sin, pluck it out and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell.
30 And if your right hand causes you to sin, cut it off and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell.
Then He adds- FUTHERMORE which means in addition, but notice how He ties divorce under most circumstances with one of the Ten Commandments
31 "
Furthermore it has been said, 'Whoever divorces his wife, let him give her a certificate of divorce.'
32 But I say to you that whoever divorces his wife for any reason except sexual immorality
causes her to commit adultery; and whoever marries a woman who is divorced commits adultery.
Oaths can be tied into the 9th commandment- lying
33 "Again you have heard that it was said to those of old, 'You shall not swear falsely, but shall perform your oaths to the Lord.'
34 But I say to you, do not swear at all: neither by heaven, for it is God's throne;
35 nor by the earth, for it is His footstool; nor by Jerusalem, for it is the city of the great King.
36 Nor shall you swear by your head, because you cannot make one hair white or black.
37 But let your 'Yes' be 'Yes,' and your 'No,' 'No.' For whatever is more than these is from the evil one.
Love for our enemies is the greatest commandments and we cannot love God or neighbor by breaking the commandments of God 1 John 5:2-3
38"You have heard that it was said, 'An eye for an eye and a tooth for a tooth.'
39 But I tell you not to resist an evil person. But whoever slaps you on your right cheek, turn the other to him also.
40 If anyone wants to sue you and take away your tunic, let him have your cloak also.
41 And whoever compels you to go one mile, go with him two.
42 Give to him who asks you, and from him who wants to borrow from you do not turn away.
43 "You have heard that it was said, 'You shall love your neighbor and hate your enemy.'
44 But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you,
45 that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust.
46 For if you love those who love you, what reward have you? Do not even the tax collectors do the same?
47 And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so?
48 Therefore you shall be perfect, just as your Father in heaven is perfect.
