God relates to Moses a message to give to Pharaoh and to the Jewish people before the 10 Plagues begin, "My firstborn son is Israel" (Exodus 4:22). The Israelites were at their lowest point at this time, undeserving of any miracles in their own right. And yet that is exactly when God sweeps us up, taking us out of the darkness of Egypt, initiating the upward-moving process until 50 days later when we are deserving of receiving the Torah and of becoming a nation. What a perfect time and place to give the Jewish people the encouraging message in the commandment to sanctify the new moon every month and to determine our calendar this way:
"And God said to Moses … in the land of Egypt, say to the Jewish people: This month is for you the beginning of the months …" (Exodus 12:1-2)
God has given us the power of renewal and change, the gift of expanding, brightening and growing big again after we have been diminished.

WOMEN AND ROSH CHODESH
For women, Rosh Chodesh, the first day of the new month, is considered a mini-holiday as a reward for not having been willing to participate in the sin of the Golden Calf.
After the giving of the Torah on Mount Sinai, Moses went up the mountain for 40 days to receive the 10 Commandments. As a result of a minor miscalculation, the Jewish men believed that Moses had died and they beseeched Aaron to make for them a "god" to go with them in the desert.
There is a beautiful teaching on the New Moon – ROSH CHODESH, that is great to internalize. The main point is that Rosh Chodesh is a renewal, almost like a new birth each month that can occur in my life. It is an appointed time with my Creator. As we can have a date with our husband or best friend and share that moment that has even greater significance for all of us.

Let us look in the Scriptures...
The first commandment the Hebrew folks were given as a people is the commandment of Rosh Chodesh, the New Month:
"And God said to Moses... in the land of Egypt... This month is for you, the head of the months. First it is for you among the months of the year." (Exodus 12:1-2)

The Jewish nation was told while still in Egypt that the month of Nissan, the month in which they would be leaving Egypt, the Month of Freedom, should be for them, their first month, and that from now on, they, as a nation, have a responsibility to count the months and create a uniquely Jewish calendar based on the lunar year.
Isn't this a strange first commandment? You'd think the development of the calendar would only come after the establishment of the basic fundamentals like the Ten Commandments. Why does the Torah consider the process of establishing the new month as a major breakthrough in creating a nation? This was the First Thing to do even before leaving the land of Slavery... Think, when you are slave, time is not in your hands but in your Master's hands. So creating a calendar was their first step of Freedom, they were in charge of their lives again. God told them; "Time is now in your Hands and remember to share it with me."
So creating a calendar was their first step of Freedom, they were in charge of their lives again. God told them; "Time is now in your Hands and remember to share it with me."
And what was wrong with the solar calendar that everyone else had been using? What is the significance of basing the Jewish calendar on the moon?

THE HUMAN ELEMENT
The Commandment of sanctifying the new month was a rather involved process. As soon as someone saw the tiniest sliver of a new moon, they would run to the Jerusalem High Court, who needed two witnesses to testify that the moon was actually seen. They would then convene the court, declare the new month and send messengers across the land to tell everyone that the new month had begun on this certain day. They, in turn, would pass on the news and place torches on mountains and high spots to spread the news faster. Sometimes it took two weeks for people to receive confirmation of the day the court had declared as the beginning of the month. (This, by the way, is the root reason why the Jews of the Diaspora would keep two days of the holidays, just in case they were wrong about which day was Rosh Chodesh if the information didn't arrive on time.) So that calendar determines on which day each Jewish holiday will occur. Each particular holiday brings with it a concrete spiritual reality from above that is available for us to tap into on that specific day.
God is giving the Jewish people an empowering message with this first commandment. Up until now, the Jews have been slaves to the Egyptians. Their time was not their own. Now, says God, you are becoming masters of your time. And not only of your own time, but of My time as well! By being given our own system of measuring time and creating our own calendar, we are taking charge of shaping reality. We are given a certain area of control over nature. Whereas time is steadily moving ahead, never-stopping, marching on in a cyclical, repetitive spiral, we are given the power to stop or start time at will, allowing us to "share" with God that special creativity of determining reality.

THE MOON
As part of this empowering message, it is essential for the moon to be our determining factor in setting up our calendar instead of the sun. The unique feature of the moon is that it appears to us to wax and wane, to disappear and reappear, to grow, diminish and grow again. It is also the smaller of the two luminaries.
Whereas the sun is the symbol of unchanging nature, rising in the east, setting in the west, day in and day out every day of the year, the moon changes and it seems to be telling us something: You can be small and you can diminish until you almost disappear, but then, when things look their darkest, hope springs eternal. You can start looking up again. You can change a situation and yourself for the better, no matter how bad it seems. Nothing is static or set in stone. Human beings have free will and therein is their power of renewal -- an ever-present struggle against the steady, cyclical, repetitive and predictable march of time and nature.
The solar system determines the year, in Hebrew "shana," which comes from the same root as "to repeat, to go over," whereas the moon sets the months, "Chodesh" from the Hebrew root "chadash," -- new, change, different. The people of God are compared to the moon. Though they are small, and suffering has been an integral part of their history among the nations, the Jew knows never to give up. As an individual and as a nation, he will rise up again and light up the night. We live with this belief in the power of miracles, that God supervises over the world and is not dependent on predictable laws of nature. The Jewish nation has a special relationship with God and even when on the lowest of spiritual rungs, about to assimilate and disappear, God maintains His constant love, as a father loves his son.

Its a Girl Thing
Why should this be our reward? What is the link between our not willing to give up our precious jewelry for the ill-fated Golden Calf project and the concept of celebrating the reappearance of the moon every month? Women had the ability to see beyond the very frightening situation the Jewish people experienced after Moses went up to receive the Torah and tarried on his way back. As far as the Jewish men were concerned, all hope was lost. There was no leader, no shepherd, no one to guide them through the desert to Israel. How could Moses be late? He must have died!
When things seemed dark and hopeless, the women knew that light was just around the corner.
But the women could not be convinced to sink into such utter despair. When things seemed dark and hopeless, they knew that light was just around the corner. Patience and trust in God would be all that would be needed to get through the "bad" times and into the good ones. Like the moon, becoming brighter and bigger only after it disappears completely into darkness, they knew that better times were on the way. It was impossible to them that God would leave them stranded after having just received the Torah 40 days earlier. They were willing to believe in the power of renewal and trust God no matter how difficult things seemed. Let us hope that we can take encouragement from this special gift of the lunar cycle by which we count the months.

Rosh Chodesh teaches us that everything can change. It is when a situation reaches its bleakest point that the light appears again.