The foundation of anything is what defines and supports it.
Jesus is the Truth about His HolySpirit. He is the HolySpirit in flesh.
The Grace of the HolySpirit is directly connected to the perfect, finished work that Jesus accomplished.
Without Jesus, Grace could not have been given and so every human would be doomed to the LakeOfFire.
This verse tells us that any attempt to know ^God^ or worship ^God^ apart from Christ Jesus is simply a waste of time. It is futile.