This week’s parasha speaks about the importance of being kaddosh-holy.
A man under the chuppah tells his bride הרי את מקודשת לי - You are holy to me - what does that mean? He is telling his wife under the chuppah that you are special and unique to me.
Hashem tells us to be kaddosh because we are different than the world out there: we eat differently; speak differently and have different goals and commandments. We were handpicked by Hashem out of all the nations to be his nation a 'mamlechet kohanim vegoy kaddosh' a kingdom of priests and a holy nation therefore we need to act differently than others, we need to be kaddosh - holy. Through this we get closer to Hashem and our goal is fulfilled. But how do we become kaddosh - holy?
The answer is by learning Torah and keeping the mitzvot and changing the way we act we become holy as we say in blessings over mitzvot "אשר קדשנו" - You make us holy through performing your commandments - through these mitzvot we sanctify ourselves and get closer to our Creator. The more the mitzvah is done with love and devotion the more it sanctifies us.