The essence of the festival of Shavuot, the time of the giving of the Torah, with the final redemption, is elucidated by Rabbi Ashlag in his commentary, the Sulam, on this beautiful piece of Zohar.
Here is a class given by Yedidah. The Aramaic and Hebrew is presented. The translation and discussion are in English.
You can access the text of the Zohar and Perush HaSulam here
Listen to class (36 minutes)