For example....

During the Mosaic period the hand of a person was cut off in punishment of a small theft; there was a law of an eye for an eye and a tooth for a tooth, but as these laws were not expedient in the time of Christ, they were abrogated.

Likewise divorce had become so universal that there remained no fixed laws of marriage, therefore His Holiness Christ forbade divorce.
According to the exigencies of the time, His Holiness Moses revealed ten laws for capital punishment.

It was impossible at that time to protect the community and to preserve social security without these severe measures, for the children of Israel lived in the wilderness of Tah, where there were no established courts of justice and no penitentiaries.

But this code of conduct was not needed in the time of Christ.