Inspiration that comes from on High is energy. That energy trickles down and is filtered through Hishtalshelus until it “thickens” and becomes the inspiration in your surrounings. (Hakdama, Siddur Torah Ohr. V’Hinei Porach, [Parshas Korach] Likkutei Torah).

An is’arusa d’l’eyla (literally, an awekening from Above) is an abstract term referring to this type of experience. It manifests itself in the form of, say, waking up in the morning feeling good, feeling energized during davening or doing a mitzvah, etc. The downside is: as easy as it comes, is as easy as it goes. Since it never penetrated the core of the person and thereby there was never any decision or change of will made, the feeling of inspiration fades.

An is’arusa d’l’eyla comes as a result of hard work and personal effort (is’arusa d’l’tatta, literally, an awekening from) or on it’s own when Hashem nudges us out of our old frame of reference and headspace. Feeling inspired is a good reason to commit to certain resolutions (is’arusa d’l’tatta) so that when the inspiration does fade, we still have our relationship with G-d.