Things surpassing human understanding

... from cosmology:

either of

The Universe has a beginning.
The Universe has existed eternally.

either of

The Universe is bounded.
The Universe in unbounded.

... from religion:

The Christian doctrine of the Trinity.

... and from politics:

Liberals who question a Republican administration's motives are treasonous.
BUT
Conservatives who advocate violence against a Democratic administration are patriotic.

Human reason simply is not sufficiently evolved to understand these things.