Two brief teachings by R. Kalonymus Kalman HaLevi Epstein on Shavuot, excerpted from Maor vaShamesh
ויחן שם ישראל נגד ההר And Israel camped there under the mountain. Exodus 19:2
Rashi points out that ‘camped’ is in the singular, and explains they camped there ‘as one person with one heart.’
To receive the Torah, the essential thing, on which everything else depends, is that there be love and brotherhood among the children of Israel, as our sages said, ‘The entire Torah depends on the mitzvah of love your fellow as yourself.’ For when there is peace among us, the divine Presence rests among us, since the totality of our souls equals 60,000, the number of letters in the Torah, for we each have our soul’s root in one of the letters of the Torah — and this is hinted at by the very word ישראל ‘Israel,’ which stands for יש ששים רבוא אותיות לתורה, yesh shishim ribo otiot latorah, ‘there are sixty-thousand letters in the Torah.’ So, when there is peace among us and love and brotherhood and fellowship, we are fit to receive the Torah, for through our joining together is the Torah made complete, and with ease can each of us join to our root in the Torah. So, at the time of the giving of the Torah Israel ‘camped with one heart,’ thereby meriting the Torah and revelation of the Shekhinah face to face.
In the Zohar it is written that ‘the Blessed Holy One and Torah and Israel are one.’ This does not mean one as in the number, so that two should follow, rather that all is one single and simple unity, for our souls and the Torah are all emanations of God’s own essence. And I heard from my teacher Elimelech of Lizhensk on the verse, God spoke all these words to them saying, ‘I am Hashem your God,‘ that the Blessed Holy One gave all of the Torah so that we could understand Him (1)… So we find that all of the Torah is included in [the first word of the Ten Commandments] anochi, ‘I.’
Sources: The entire Torah depends…Shabbat 31a; God spoke…Exodus 20:1
1) To make the point clearer, the word ‘saying,’ lemor, can also be read ‘[in order] to say.’