Holding A Lulav During Prayer

23 of the Seventh Month/Isru Hag 5770

משנה תורה הלכות תפילה ה,ה
...ובכל מקום, לא יאחוז תפילין בידו או ספר תורה בזרועו, מפני שליבו טרוד בהן; ולא יאחוז מעות וכלים בידו. אבל מתפלל הוא בלולב בידו בימות החג, מפני שהיא מצות היום

Mishnah Torah Laws of Prayer 5:5
...one does not hold Tefillin in his hands or a Sefer Torah in his arms, because they will worry him; and one does not hold coins or vessels in his hands. But one who is praying has a lulav in his hand during the Hag [HaSukkoth], because it is the misswah of the day.

This was how prayed during Sukkoth.

Of course, I also wore Tefillin during Hol HaMo'ed:

(Machon Shilo) Both Talmudhim indicate that one is to wear Tefillin during Hol HaMo'edh.

The Rif, Ramba"m, Rosh and Tur all agree that the misswah applies even during Sukkoth and Pesah. The Shulhan Arukh says otherwise, contrary to his own rule of thumb. He was influenced by the Zohar, classic and telling example of the influence of Qabbalah on Halakhic practice. (Click the link above for audio shi'urim on this topic.)