Holy Zohar text. Daily Zohar -304.

Tikkun 21 – 45

When Zeir Anpin and Malchut connect, they elevate the lower waters up through the central column to the supernal mother, which is Binah.
There are 25 levels on the right column and 25 levels on the left column. Those are the 50 gates of Binah.
Binah has 10 Sefirot and each has its own 10 inner Sefirot and together they make 100 levels. When Malchut reaches Binah, they split to 50 and 50 and get pushed up to the supernal Father and Mother and to Israel Saba and Tevunah that are above Binah.

When we recite the [audio:http://dailyzohar.com/wp-content/uploads/2010/04/ShemaIsrael.mp3] Shema Israel שְׁמַע, יִשְׂרָאֵל: יְהוָה אֱלֹהֵינוּ, יְהוָה אֶחָד.
in the morning and in the evening with twice the 25 letters of the unification line, we have 50 to help us climb through the gates all the way to Binah.
The Morning connection is the aspect of the right column, the afternoon is the left and we don’t recite the Shema. The evening is for the central column and the Shema prayer balances the right and the left. This is the secret of
וַיְהִי-עֶרֶב וַיְהִי-בֹקֶר, יוֹם אֶחָד
“And there was evening and there was morning, one day”
When we say the last word אֶחָד, we should ‘stretch’ its sound and meditate to bring the two columns as one.