"They are Slaves to me - Not Slaves to Slaves"
Summarized by Rav Eliyahu Blumenzweig
In Parashat Bo, we witness for the first time the appearance of a set of practical mitzvot. In essence, most of these mitzvot are related to the Exodus. The first mitzva of this set, however, that of Kiddush Ha-Hodesh, is seemingly an exception. We may therefore ask ourselves in what way is it connected with the great event of the Exodus.
We may begin to understand this by noting a particular halakha cited by Rabbeinu Tam, according to which a laborer may decide to cease his work at any time, based on the principle that "they are slaves to Me, not slaves to slaves." On the other hand, a different law applies to the contractor, who is not able to give up his work at any time he chooses.
Hence, there is a qualitative difference between the contractor and the laborer. The laborer is a slave, while the contractor is not.
However, what really is the difference between them? It seems that the source of the difference lies in that the laborer's submission to a time-frame is dictated to him by his master. The laborer has no regulation of his work other than the constraints of time. He is enslaved to a certain framework of work hours, in which he may do nothing but the work of the owner. His obligation in this regard is so great that the Chakhamim absolved him from saying the fourth berakha of Birkat Ha-mazon - in order that he not waste the master's time.
This is not the case with regard to the contractor. The contractor takes upon himself the execution of a certain task, and he is free to plan his work timetable in whichever way he chooses. He is not forced to do his work during certain hours. He is not a slave of time, but rather its master and ruler.
This point characterizes the mitzva of Kiddush Ha-Chodesh. The determination of time was placed in the hands of Bnei Yisrael, as it is written: "This month will be for you the First of Months..." - the time is given to you, to use as you see fit. This is the essence of freedom from slavery.
This freedom from the yoke of time also finds expression in the halakhic and social spheres, as explained above, in relation to the laborer and the contractor. But its significance is far greater.
Within the mitzva of "This month will be for you..." lies the command to number the months of the year starting from Nissan. In other words, years are no longer to be counted from the Creation, but rather from the Exodus. This is not merely a technical difference, but rather represents an important and fundamental shift. A qualitative difference exists between relating time back to the Creation and relating it to the Exodus.
Relating to the Creation lends time something of the spirit of the Creation, a kind of partnership with the natural world, a world in which a person acts in a given and bounded space which limits his freedom of action. Nature confines his steps, with time representing one of the chains which confine him.
Relating time to the Exodus, on the other hand, places man in the framework of history, and he therefore feels that he is part of an all-encompassing process. Here, he is not chained and confined, but rather an active and creative agent. With his own hands, through his own actions, he determines his progress. He is not swept through life's currents against his will; rather, he has the responsibility of directing, navigating and leading his own way. He no longer acts as an "object", but is now a "subject" - a subject with free choice, with a will of his own, with the ability to act.
When a person relates to the world from this point of view, he is freed from enslavement to nature. He is no longer a slave to the laws of nature, but rather he is able to control them, and to act as he wills. He may rise and progress without nature interfering with him. He is free to act and to navigate his path towards God, to venture towards and to arrive at his true Master. Indeed, "they are slaves to me - not slaves to slaves": we are slaves to God, not slaves to nature.
(Originally delivered on Leil Shabbat, Parashat Bo 5732.
Translated by Kaeren Fish.)