Yogaswami’s wrote powerful spiritual letters to his devotees.
Here are two to a young man, Yogendra:
Letter to Self who is Yogendra full of Love.
I am with you and you are with me. You are myself and I am you. What is it you fear? Look! I am you. Then what would you do? You must feel and show love. To whom? To everyone. In fact your nature is nothing but love. It is not only yourself, but the whole universe which is overflowing with love.
Yet it is not any other, because you are the only one in existence. You are all things. Study well. Be obedient. Listen to and follow the advice of your father, mother elder sisters, younger brother, as well as your uncle, aunt and elder brothers. Always set an example in obedience.
Siva does all
I am you.
Look: everything is Sivamayam. Then who are you? Who am I? Who is your father? Who are they, and what are all others? Are they not all Sivam? Are you still in doubt? Do you fear? Look! I in you, and you in me, and all being ONE and ONE being all, remain changeless as ever before. Arise, know more and more.
Bodhinatha's Latest Upadeshas: "The Difference in Practice of Theism and Monism" (September 3, 2014)
During a puja we're in Theism, to receive the blessings of the Deity. After a puja we can go within our self in meditation, giving up the idea of an external Deity, Monism. Monistic Theism: Advaita Ishvaravada. Advaita means the Monism; Ishvara means the Theism.
In Shum we use two words that relate to that: shumif and dimfi. First, perfect your Theism. Then become a monist. That's called Saiva Siddhanta; one leads to the other.