The counting of the Omer is a process of building the vessel with purity to achieve completion on the fiftieth day. On that day we celebrate Shavuot, which is a connection to Mount Sinai and the receiving of the Torah. A great light of immortality is then revealed and a pure vessel would benefit greatly.
Many reads the Gate of Holiness by Rabbi Haim Vital. In this book he guides the spiritual person to the path of holiness going through the different actions one should do to achive such a high goal.
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