It states (38:27), אדני את לצקת הכסף ככר מאת ויהי אדנים מאת ...הקדש, "The one hundred kikar of silver should be used to make the holy adanim – one hundred adanim..." These were the 100 silver foundations of the Mishkan.
The Baal HaTurim writes, ברכות 'ק תקנו כנגדם יום בכל, "Corresponding to the one hundred adanim the chachamim established one hundred daily brachos."
The Chidushei HaRim zt'l says that Hashem resided on the Mishkan, and today Hashem resides in Yidden. The Mishkan in our generation is every single Yid, when he merits that Hashem resides in him. The original Mishkan had one hundred adanim for its foundations. The foundations of today's Mishkan are the one hundred daily brachos we recite. They are called אדנים because with them we become aware that Hashem is the אדון, master of the world.
The Tur (Orach Chaim 46) writes, "Every day, one hundred people of Bnei Yisrael died, and they didn't know why this was happening. Dovid HaMelech investigated, understood with his ruach hakodesh, and instituted that Klal Yisrael should recite one hundred brachos every day. Therefore, the chachamim established birchas hashachar [the brachos said in the morning at the beginning of the tefillah] to fill the quota of one hundred daily brachos".
The Prishah explains, "When a hundred people were dying each day, Dovid established that we say one hundred daily brachos, because that will stop the deaths... Dovid taught the secret of one hundred brachos to the Sanhedrin, so they should institute the brachos as they see fit. They established the brachos with their wisdom..."
How did the one hundred brachos halt the daily one hundred deaths?
The Levush explains that Hashem does much kindness with the Jewish nation, but people take it all for granted, and they don't express their gratitude to Hashem. Dovid HaMelech realized that this was the source of the plague, so the solution was to praise Hashem. The solution proved to be correct because "from the time Dovid instituted this takanah, the plague ceased."
The sefarim say that just as one hundred brachos daily saved us in the past, they continue to provide protection for all generations.
