Holy Zohar text. Daily Zohar -261.

Tikkun 21 -3

The prayers ascend through the 10 letters of the name of Zeir Anpin יודהאואוהא. We need at least 10 men to establish a connection.
Negativity will try to grab the weak prayers. As it is said in Deuteronomy 25:17,18 “ זָכוֹר, אֵת אֲשֶׁר-עָשָׂה לְךָ עֲמָלֵק, בַּדֶּרֶךְ, בְּצֵאתְכֶם מִמִּצְרָיִם”
“Remember what Amalek did unto thee by the way as ye came forth out of Egypt;”
“אֲשֶׁר קָרְךָ בַּדֶּרֶךְ, וַיְזַנֵּב בְּךָ כָּל-הַנֶּחֱשָׁלִים אַחֲרֶיךָ–וְאַתָּה, עָיֵף וְיָגֵעַ; וְלֹא יָרֵא, אֱלֹהִים”
“how he met you along the way and attacked among you all the stragglers at your rear when you were faint and weary; and not fear God..”

When the Israelites were on the way to the Promised Land, Amalek, representing all negativity in a form of doubt in the light, grabbed all the weak and corrupted the connection of the Israelites to the Holy Land. It caused the sin of the Golden Calf and the sin of the 10 spies.
In order for all the prayers to ascend to the gates or prayer, all prayers must be included.

This is why all our prayers are recited in plural form. Only with unity we can reach our destination and enter the ‘Holy Land’ to enjoy ‘Milk and Honey’.