We mentioned last week about the concentration during davening that was required in the Yeshiva of Kelm. Therefore, it was very surprising one time when in the middle of davening, the Alter of Kelm got up from his seat, walked to the back of the room, flipped through a siddur he picked up from there, and finally returned to his spot where he was davening. After the service was over he explained he did this because there was a stain in his siddur and he could not read one of the words. He therefore, needed to take a different siddur to say that word. A person should be very careful to say every word of davening!