The נחש הקדמוני is the root of Amalek. That is why עמלק is gematria ספק b/c Amalek instills doubt in Hashem as did the נחש when he tried to convince חוה that she doesn't have to listen to Him. "C'mon, Hashem is afraid that if you eat from the tree you will know between good and evil like Him".
After the sin it says הנחש השיאני ואוכל - The snake seduced me into eating from the forbidden fruit. The pasuk says that the Jews were in doubt "היש ה' בקרבינו אם אין" Is Hashem among us or not? Right after that it says ויבא עמלק. You doubt Hashem, Amalek comes! "היש אין" is the same letters as השיאני. [Rav Wolfson Shlita]
One well known MO rabbinic personality famously said that faith is not certainty but the courage to live with uncertainty. No, actually uncertainty is Amalek. True Faith is certainty.
Rambam: יסוד היסודות ועמוד החכמות, לידע שיש שם מצוי ראשון. What does that sound like? Certainty or uncertainty??
We all doubt at times and that is human. But we have to work to overcome it. Who wants to live w/ Amalek??
