Holy Zohar text. Daily Zohar -64.

The prayer of Shema Israel has 25 letters and six words. It creates unification between upper and lower. When God instructed the priests to bless the Israelites he said “So you will bless the Israelites…”. The Word “So” in Hebrew KH כה has numerical value of 25, same as the number of letters of the beginning of this prayer. This prayer recites twice a day, morning and evening and 2 x 25 is 50 to make the connection to Binah. The six words are for the channel of Zeir Anpin to fulfill the unification and transfer the Light from above to below.
There are many powerful codes in this special prayer, which some we discussed in previous commentary.

The first part of the Shema prayer is also put inside the Mezuzah on our doors to provide protection and blessings to our homes.

מקור הקטע: הקדמת תיקוני הזוהר עם פרוש מעלות הסולם (רבי יהודה צבי ברנדויין זל) פסקה 314