My cats and my baby ...

We brought our little one home yesterday and our 2 cats didn't give him a very nice welcome ! One if them even hissed at me and my mom...  They won't come near us or the baby and they seemed very scared and alert . I even had my husband bring some of the baby stuff the previous night so they could get used to his smell . I don't know what to do. I'm really worried they will scratch him  . I love my cats but my baby comes first. Has anyone else experienced this before and how did you deal with it?