For all of Israel are responsible for one another.
Sanhedrin p 27b; Shavuot p 39a
“And Israel camped there, opposite from the mountain” (Exodus, 19). Our sages interpreted—as one man in one heart.
Baal HaSulam, “The meaning of Conception and Birth”
Israel are responsible for one another, meaning that the whole of Israel are one discernment.
Rabash, Steps of the Ladder, “Bride and Groom”
Through the force of Arvut [mutual guarantee], one corrects for another, and everything is corrected.
Ramchal, Drushei, 24 Kishutei Callah [Adornments of the Bride]
It is presented in Midrash Tanchuma, “Israel will not be redeemed until they are all one society, as it is said, ‘In those days and at that time, says the Lord, the children of Israel shall come, they and the sons of Judah together.’ Thus, when they are united, they receive the face of Divinity.”
I presented the words of the Midrash so that you don’t think that the issue of a group, which is love of friends, relates to Hassidism [a branch of Judaism]. Rather, it is the teaching of our sages, who saw how necessary was the unity of hearts into a single group for the reception of the face of Divinity.
Rabash, Rabash—the Social Writings, “Letter no. 34”
This is to speak of the Arvut [Mutual Guarantee], when all of Israel became responsible for one another. Because the Torah was not given to them before each and every one from Israel was asked if he agreed to take upon himself the Mitzva [precept] of loving others in the full measure, expressed in the words: “Love thy friend as thyself.” This means that each and every one in Israel would take it upon himself to care and work for each member of the nation, and to satisfy all their every needs, no less than the measure imprinted in him to care for his own needs.
And once the whole nation unanimously agreed and said, “We shall do and we shall hear,” each member of Israel became responsible that nothing shall be missing from any other member of the nation. Only then did they become worthy of receiving the Torah, and not before.
Baal HaSulam, “The Arvut [mutual guarantee]”
When one feels that one’s soul exists in the whole of Israel, in each and every one of them... At that time, he is complete, flawless, and the soul truly shines on him in its fullest power, as it appeared in AdamhaRishon.
Baal HaSulam, “600,000 Souls”
“There is a certain people scattered abroad and dispersed among the peoples.”
Haman said that in his view, we will succeed in destroying the Jews because they are separated from one another; hence, our force against them will certainly prevail, as it causes separation between man and God. And the Creator will not help them anyway, since they are separated from Him. This is why Mordecai went to correct that flaw, as it is explained in the verse, “the Jews gathered ,” etc., “to gather themselves together, and to stand for their life.”This means that they had saved themselves by uniting.
Baal HaSulam, Shamati [I Heard], 144,
“There is a Certain People”
“You are all beautiful, my wife.” “The whole of the soul shall praise the Lord.” The perfection of Divinity is in the soul of the Messiah King, who is an only daughter. However, to be complete, all the other souls must bond within her, and they all become one within Her, and then Divinity shines with great correction, for she is a bride. And then, “You are all beautiful, my wife, and there is no blemish” that remains, for through the force of the Arvut, one corrects for another, and everything is corrected.
Ramchal, Drushei, 24, Kishutei Callah [Adornments of the Bride]