When Yidden look out for one another, miracles happen on a regular basis... because the power of every Yid is combined with that of the others.
Recently, a Yid who was marrying off a child publicized the following:
I was married for several years without children. One day, I went out with some other Yidden in a similar situation, in order to strengthen each other. There, we decided that each one of us would take the name of another person and daven for that couple to be blessed with a child. I chose the name of a specific person, and we began davening for each other. Not long afterward, we were blessed with a daughter, and the incident was forgotten.
Eighteen years later, my daughter became engaged to a wonderful boy, when suddenly it hit me—this boy is none other than the son of the person for whom I davened!
The kallah and the chassan were each born from the tefillos of their future in-laws! What an incredible power of davening for another person: כל תחילה נענה הוא דבר לאותו צריך והוא חבירו בעד המתפלל.
