Your source claims that "it is abundantly clear that it is impossible for anyone to comprehend the Essence of God" and that god cannot be described or understood by anyone, regardless of how much we contemplate it.
And yet, the Baha'i faith relies fundamentally on comprehending, understanding and describing many aspects of god.
I mean, if it really is impossible to understand anything about god, then every claim about god by anyone claiming to have any understanding of god is obvious bull**** and should be dismissed as such.
It is a sound teaching that reflects why the thoughts of men are so divided on the topic of God. Truth is relative to our own nature, nurture and then choices.
Now we also get to answer this OP, as all the Prophets and Messengers sent by God are the only way we can know God, in Attributes. The Attributes are the Essence of the Messenger, they are the mirrors of the Spirit that emanates from God, they are the 'Self of God' to us in the matrix.
Thus as it has been previously offered. It is the person, their life and the Message that distinguishes the Prophets and Messengers from other human beings. As they are born of that Holy Spirit and not of the human spirit.
But unless in is open that there is levels to.spirot that sustain creation, then all this will not even be considered.
Nature, nurture and our choices create the world we live in. The best of choices can be found in what God has offered via the Messengers. History has proved that they have the greatest power to unite the souls and hearts of humanity, in this age Baha'u'llah has cone to unite the entire human race and the Message he gave is the only way we can unite, it contains all the required guidance needed in this age.
Regards Tony