Light Of The World

א"ר ברכיה מ"ד והארץ היתה תהו ובהו מאי משמע היתה שכבר היתה ומאי תהו דבר המתהא בני אדם ומאי בהו אלא תהו היתה וחזרה לבהו ומאי בהו דבר שיש בו ממש דכתיב בהו בו הוא
Sefer HaBahir, verse 2

There is one sofit (final) tzadi ץ in the entire verse. In addition to this letter, there are 120 other hebrew letters.

Tradition teaches that once one has added a hebrew name(s) to the name of his or her birth, a person is to be called by that name until 120 years. Here is that 120 "years", where the hebrew root letter shin ש of the word "years" alternatively means "change". In other words, one is called by the added name until a quantity of "change" in the amount of "120" [1] has been reached.

With respect to ץ, G-d saw that the light was good ... Bereshit 1:4.

R' Michael Munk (Wisdom In The Hebrew Alphabet) writes of this light:

The light that G-d found to be good was the deeds of the tzadikim (Yalkut Eliezer).

Shir HaShirim Rabbah 5:1:

The tzadik (tzedeket, feminine) illuminates the world by bringing the shechinah down to dwell among humankind.

Making this personal, in my own life, when I returned to Torah, I choose hebrew names. Now clearly, the utlility of that name has fulfilled its purpose - to bring me to the status of ץ, able to stand on my own name. Whatever I decide that name may be.

Footnote:

[1] 120 = מיסוד (see Messianic Mikveh)