Zohar and Sefer Etz Chaim

Both texts address yesod and sitra-achra in relation to divine flow and blessing. Text 1 emphasizes the distinction between external vessels (כלים חיצונים) where the serpent of smallness resides and the internal yesod where genuine influx (מ"ן) occurs. Text 2 discusses how yesod receives blessing from Netzach and Hod, but also how sitra-achra can attach to these channels during certain periods ('שלושה חודשים'). Text 1 stresses the boundary/protection between realms (לא בפנים), while Text 2 emphasizes the vulnerability of yesod to sitra-achra influence under specific conditions. Both acknowledge sitra-achra's relationship to yesod, but Text 1 presents a structural separation while Text 2 presents a dynamic oscillation in dominance.