Sometimes people say that they want to “become spiritual”. While this is a good sentiment, in reality no one can become spiritual because we (our true selves) are already spiritual. That is our eternal condition, no matter what kinds of efforts we make.
However, what can (and usually does) happen is that we forget our spirituality by adopting a false self (ego), which is a nonspiritual thought system. So all we can do via effort is pretend that we are not spiritual. Hence when we get tired of being egoic, and/or start to wake up from the egoic dream, it might seem that we are “becoming” spiritual. In actuality we are remembering the spirituality we had all along.
When one becomes a spiritual seeker, who seeks? The false self. Only something nonspiritual would seek to become spiritual, and only via the false self can we seem to not be spiritual. Since the false self can never become spiritual (because it is inherently nonspiritual), it is doomed to fail. As long as we believe ourselves to be the fabricated false self, we are hiding from our spirituality, from our true selves. Only when we drop the mental construct of ego can we see clearly and feel the spirituality that is us.