Sparks left over are as visions in the night
How can you understand that sparks remain in the vessels that were broken in the world of Tohu? If the lights can be 'broken' and simply were nistalk - (removed themselves upwards) , how can any lights remain in the vessels? The mashal - an allegory to understand this are the sparks that remain from the letters of your thoughts and speech during the day that form the dreams you have at night. (Dreams are a birrur - purification/elevation of these netzuzot - similar to how mitzvot - good deeds are mevarer - purify the sparks in klipat noga) Rebbe Rashab - 1905 Ve'yigdelu ha'ne'arim