What does that word ‘sanctified’ mean? It literally means ‘to separate something (from other things).’
When I was growing up, I remember when we were getting dressed to go to church, my mom or my grandmother, depending on where we were, would tell us to put on our ‘Sunday clothes.’ Or if you were going to a wedding or a funeral, you would ‘put your Sunday clothes on.’
Now, did you wear your Sunday clothes to school? No. Did you wear your Sunday clothes to play in the yard? No. To play football or baseball? No. To work on the farm? No.
Those clothes were separated from the rest of your clothes. They were set apart for certain occasions.
In the Scripture, when we are separated from sin (from things that are immoral or ungodly) and we are set apart for fulfilling His will and purposes, we would be described with this word.