When the external forces grab spark the result is that Hashem grabs the nai of ABA from the nai of IMA. So the external forces would not get to the nai of ABA. All this process, as a consequence, ends up in a “sickness” of SER ANPIN. The nai of ABA is the י–ה–ו–ה and IMA ‘S is “EKIE”. Therefore, when the nai of ABA is removed, the nai of IMA becomes backwards; which is the gematria of “dam (blood)”.
 

One of the main goals of this meditation is to bring back the nai of ABA into IMA, since IMA is in a state of “ribua”. They have to be combined, meaning: the י–ה–ו–ה with the ribui of IMA (EKIE) within Zer Anpin. The result of this combination is the combination of the י–ה–ו–ה with EKIE (not in a ribui form anymore)in the nai of IMA. 
 

To explain this process the Arizal brings a parabole: it is like a newly born that cannot have a Brit Milah because the organ is too red. So it has to be cleared from the blood for it to be able to go through the Brit Milah. 

The meditation of the Absorption of the Blood is done every day for the 5 Chasadim and the 5 Gevurot. These 5 Chasadim and 5 Gevurot have to be done to the Sefira corresponding to each day of the “Counting of the Omer”...