Musar על קידושין 81:17

We have learned in Kidushin 41: The commandment to be מקדש את האשה devolves first and foremost on the actual groom, though it may be performed by anyone he designates. When the Jewish people left Egypt, G–d (the groom) personally performed the act of קדושין: The Torah says of G–d: ועברתי בארץ מצרים (Exodus 12,12). The ceremony was, however, also performed by a messenger whom G–d had designated, viz: וישלח מלאך ויוציאני, "He sent an angel (messenger) and took me out" (Numbers 20,16). The actual wedding ceremony, the נישואין, must be carried out by the groom personally, not a stand-in. The giving of the Torah at Mount Sinai symbolised this wedding ceremony between G–d and the Jewish people. This wedding took place on the Sabbath, an occasion when G–d spoke to Israel פנים בפנים דבר ה' עמכם, "Face to face did G–d speak with you" (Deut. 5,4). The usual time for man and his wife to join conjugally is on the Sabbath. This is part of the mystical aspect of marriage.

Let me now explain the significance of the various ages as mentioned in the ערכין legislation. Our sages (Rosh Hashanah 2b) have said that a single day is considered as a whole year [under certain circumstances, such as a king who was appointed on the last day of the month of Adar. Ed.]. By applying the same rationale, i.e. that there is a cut-off date which determines who or what belongs to a certain year, we can view the Torah's statement מבן חודש עד בן חמש שנים, as a reference to a five year old, since no change in the evaluation takes place until after that child is over five years old. The same applies to people between the ages of five and twenty. They are viewed as if they were twenty years old. Once a person is over twenty and qualifies for military service, he is considered as if he were sixty years old, [the age at which military duty terminates. Ed.] During these years a person's value is considered at its maximum, and his value is based on the number י-ה, i.e. ten times five=50 shekel. A female of the same age group is evaluated at thirty shekel based on a calculation of ו-ה, six times five=30 shekel. Between the ages of five and twenty, the period during which a male is supposed to wed a woman, he is evaluated as 20 shekel which is expressed in terms of the letter י spelled as a word, i.e. יוד=20. A female of the corresponding age group is also evaluated in terms of the letter י but in her case we spell the number ten as a letter, i.e. י instead of as a word. Her value is therefore determined as being ten shekel. Since the method of writing a letter as a word is called מילואים, and the full spelling of the word יוד is achieved by the addition, i.e. מלוי, of the letters ד-ו, there is a clear symbolism here, seeing that woman is to man is what ד-ו is to י. We find a sort of confirmation of this analogy in an Aramaic proverb quoted by the Talmud Kiddushin 41a: טב למיתב טן דו מלמיתב ארמלו, "better for (two) to dwell together than to live (alone) as a widow." A woman views herself as man's complement. We therefore find that man and woman together are still considered under the concept of י, i.e. either as regular י, or as יוד במילואו. A similar calculation applies when either of the male or the female is between the ages of five and twenty. They are then evaluated under the concept of ה. When the Torah describes the value of the male as five shekel and the value of the corresponding female as three shekel, the "three" is alluded to as a complement to the male in "three" ways.