Only for the final plague are the Israelites finally required to act to obtain their freedom. 

The imperative to smear lamb’s blood on their doorpost is curious. Surely God did not need to see blood on a doorpost to know whether it was an Egyptian or a Jewish house. 

The blood was not for God; it was for the Jewish people themselves —“the blood will be a sign for you”. According to the medieval commentator Rashi, the blood was actually painted on the inner side of the door. As such it was quite literally only to be seen by the Jewish people.

Why was this ritual so important in sealing their fate? Assimilation was high and many Jews were steeped in local pagan practice. This was a moment of confrontation. They had to decide if they really wanted to leave Egypt and everything it represented. 

By slaughtering and displaying the blood of a sheep, which was an Egyptian deity, they were overtly rejecting Egyptian society. 

Isaiah Berlin’s ground-breaking essay in 1958, entitled Two Concepts of Liberty, developed the idea that there is negative and positive freedom. 
Negative freedom is freedom from interference by others. Positive freedom refers to acts of autonomy by the individual. 

These two elements are present in the Exodus narrative. Until now, God has been securing the negative freedom of the Jews; now they have to grab hold of their destiny by acting with positive freedom.

The Midrash takes this one stage further by relaying that on this same night, Jewish males carried out circumcision. The blood of the paschal lamb signifies our detachment from Egyptian civilisation; the blood of circumcision signifies our embracing Judaism and looking towards the future. On Pesach we were not just liberated, we were redeemed.

It is not enough to feel liberated by the absence of restraint; it must also be motivated by the presence of something. This year our Judasim has been stripped down. We can see the lack of communal gatherings and synagogue services as a travesty or an opportunity. An opportunity to be alone with our faith, and explore our own positive freedom and connection to our heritage.