It says in the portion Vayakhel-Pekudei that the Creator speaks to Moses and Aaron in Egypt and tells them the month they are in, which is the month of Aries, or Nissan, is the month in which the Redemption and going out of Egypt will occur, and that it should be the head of the year, counted as the first of the twelve months of the year.
Rashi, the great kabbalist and commentator, says that when the Creator is telling this to Moses, He is actually speaking to him in the beginning of the month, and showing Moses what the moon looks like. The moon shines in its complete form only on the 15th of the month, and then it begins to wane until it's almost invisible to the human eye. Then, the light of the New Moon begins to shine in a sliver, as a sign of the beginning of the next month. The Creator tells Moses this is what the moon looks like at the beginning of the month, and that when one can see the moon beginning to shine, the new month begins.
But the Creator is actually telling Moses two things here, Rashi says: one - a technical decision about when the month or year is going to start, and two - the amount of moonlight you have to see in order to begin a new month and make it holy. In every new month, you should sanctify and make the month holy, meaning, when you view the moon beginning to shine, that's how you know you sanctify, or elevate and begin, the new month.
What is the spiritual significance of this?
The great Spanish kabbalist Nachmanides says at the beginning of the process of Pesach is the bringing of a sacrifice, the Taleh, in which each family member would bring a young sheep. He says the reason for this is that the astrological sign of the month of Aries is a sheep, and on the 15th day in the middle of the month is when the astrological sign is the strongest. Therefore, the Creator says on the 15th day, which is when Pesach is, is the time you sacrifice the sign of that month to show and awaken the understanding that the going out of Egypt had nothing to do with the astrological sign.
But there is a deeper level to this which Nachmanides reveals. Every one of us has a nature we are born with, which is the nature the astrological signs dictate, and we learn that our spiritual work is to go against our nature. We all have good nature and bad nature, but when we speak kabbalistically about the purpose of our lives, it is not simply to break our negative nature, but to also go against our positive nature. Our lives need to be lived outside of nature, even positive nature.
If we had a clear vision of our lives, we would realize that 99% of everything we do, good and bad, is not really by a forced change, but rather by our nature. Think about the positive things that you did all day today, yesterday, or in your entire life. In truth, how much of that was against your nature? A very small percentage most likely.
So, we ask the question, why is the teaching of the sanctification of the New Moon and the reading that Aries is the first month of the year so important? Because it is the month when nature was completely nullified. Nachmanides tells us the sheep was sacrificed on the 15th day in the month of Aries, when the control of the nature of that sign was the strongest, because the Israelites – and us, today - had to awaken the Light that they were going to kill their nature at its most powerful time, on the 15th day of the month. The one thing we definitely don't want to be is a person who lives within the confines of his nature, good or bad. Even if it’s good, it is not OK to be a person confined to his good nature; there has to be a sacrifice, an annulment, of the force of nature.
What is the whole concept of the month of Aries, and of Pesach? That the Israelites came to the understanding that they were making a huge shift and were sacrificing and destroying the force that nature had upon them, to the degree that they could. And, what is the whole concept of sanctifying the month? At the beginning of the month, in the Upper Worlds, the nature of our month is set up; the good things we are going to do and a lot of the bad things we are going to do are all prepared. If we continue our lives as is, and even our spiritual work, we will be doing some good things and some bad things, but we are not making any changes. We might even be doing a lot of positive spiritual actions, but we are not going to be breaking nature.
It's important to realize that when we come to the beginning of the month, everything that we are going to do in that month - positive or negative - is set up for us. And most of us, unless we fight this nature, unless we begin to awaken our consciousness to this, will live our lives 99% within the confines of the scripts set up by nature, and that's a big problem, even if 80% of the month we are going to be doing positive actions. Because even 80% of the month of positive actions that are within the confines of our nature are not why we are in this world.
Therefore, in the beginning of the month, and especially in the beginning of the month of Aries which is the beginning month of the whole year, we want to break the bonds of nature and the control of the astrological signs. We don't want to live within nature, or within a life that is prepared for us.