Am confuse and I need your help

I was told by my pastor that JESUS never come to destroy the law but to fulfill it. But some verse of the new testament is confusing me.

We were told by the law to remember the sabbat and keep it holy but Jesus worked on sabbat.
Can someone please tell me how he fulfilled the law of shabbat?

2) if Jesus never come to abolish the law, why did
the law God give to Moses being referred to as the law of sin and death?


Help a brother and be blessed


Cc lalasticlala