We know that the chosson under the chupah put the ring specifically on the kallah’s index finger. The obvious question is why?
In listing the names of the five fingers, the gemara tells us the index finger is called etzba. During the plague of lice, the Egyptians were unable to duplicate it as they had done with the first two plagues, the blood and the frogs. They were forced to admit ים היא-אצבע אלה, it is the finger of Hashem. The chosson places the ring on the kallah’s index finger symbolizing that here too, it is all Hashem.
The word for a ring, טבעת, is rooted in the word טבע, nature. When the chosson puts the tabaas on the etzba, he is essentially declaring that all nature that took place in this shidduch is actually from Hashem.
Regarding why the chosson puts the ring on the kallah’s index finger, the Ben Ish Chai cites the sefer Kemach Soles that in Tehillim 19, it says והוא כחתן יצא מחפתו, like a groom emerging from his bridal chamber. There are five phrases there where the second word is Hashem’s name:
- תורת י-ה-ו-ה תמימה משיבת נפש.
- עדות י-ה-ו-ה נאמנה מחכימת פתי.
- פקודי י-ה-ו-ה ישרים משמחי לב.
- מצות י-ה-ו-ה ברה מאירת עינים.
- יראת י-ה-ו-ה טהורה עומדת לעד.
Accordingly, when one counts on the fingers of his hand starting each phrase with the thumb the name of Hashem consistently falls on the index finger. Now, by kiddushin there is a unification of Hashem’s name י-ה-ו-ה. The י corresponds to the ring; the ה, which has a gematria of five, corresponds to the hand of the chosson who holds the ring, as the hand has five fingers; the ו corresponds to the index finger of the kalla which resembles the letter ו; finally, her outstretched hand to receive the kiddushin is represented by the ה, referring to the five fingers of her hand, as ה has a gematria of five.
