Jesus was preaching under the law dispensation, thus, he cannot be telling us that. The question is, which dispensation do you regard yourself under?
Matthew 5:19
Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach
them, the same shall be called great in the kingdom of heaven.
Matt 28
18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20
Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.