Likutei Sichos – Vol 22 p 114 ff Sefiras HaOmer and its place at the end of the Siddur (by the Alter Rebbe himself). Page 114-15.

Likutei Sichos – Vol 22 p 114 ff The question: why did the alter Rebbe place Sefiras HaOmer at the end, when no one else does. It is because he holds that it reveals the very essence of what the Siddur is both on Halachic and Kabbalisitic grounds. Page 115-16.

Likutei Sichos – Vol 22 p 114 ff Beginning of the answer. Davening has a Halachic and Kabbalistic dimension and both are represented well by Sefiras haOmer and he therefore puts it at the end of the siddur. Page 116.

Likutei Sichos – Vol 22 p 114 ff Tefilla is a Mitzva that is done (also) with the heart. Page 116-17.

Likutei Sichos – Vol 22 p 114 ff Sefiras haOmer is like the essence of Davening for three reasons: ONE: because the (Cheftza of the) Mitzvah is giving (and connecting) the heart to Hashem. In Sefira the count is personal (to each individual) and he must know the meaning of the count or the count...

Likutei Sichos – Vol 22 p 114 ff TWO: The second comparison between Sefiras HaOmer and the Davening is: the first effect of Davening and Sefira is on the person who tunes in his heart and is purified and refined through this. Page 118-9.

Likutei Sichos – Vol 22 p 114 ff The third point is that if one influences only himself that is good enough, but he has the power to affect the world also, like by Sefiras HaOmer, that counts days and (also) gets us to Shavuos. The Alter Rebbe follows but does not imitate the Arizal,...

Likutei Sichos – Vol 22 p 114 ff Explanation of previous class. Sefira is first about us and second about Hashem. Two levels of sacrifice to Hashem.

Likutei Sichos – Vol 22 p 114 ff In spite of our limitations, the power of prayer of the individual is considerable. Page 120.

Likutei Sichos – Vol 22 p 114 ff Tefilla is the personal connection to Hashem that we generate that can still be infinite! It therefore changes the world more than Torah and Mitzvos. Page 12-21.

Likutei Sichos – Vol 22 p 114 ff Conclusion, The inner dimension of Tefilla is higher than a Mitzva. Why all this is represented by Sefiras HaOmer. Page 121.