If we accept that time "began" at the big bang, without time there is no before.
"At some point in the distant past, all matter and time existed, for reasons unknown, as a single point, something happened and that single point exploded decompressing initially quickly and at an ever decreasing rate, into matter and time comprising the universe."
Can we as humans comprehend more than that? I suspect not. Even that is hard. Imagine nothingness. No you're imagining an empty space, that's not nothingness, imagine nothingness, no you're still thinking of a bigger empty space aren't you, imaging nothing, nope you're still thinking of a universe with nothing in it, imagine nothing... humans are conditioned to think about things, not nothings, "before the big bang" was nothing.