Humanism concerns itself with something called the human spirit. Human spirit, as a standalone spirit, does not exist. Humans have spirit simply because they participate with life. Life is spirit. To breathe is to have spirit.
Spirituality is about recognizing and nurturing your relationship with spirit. It's communion with trees, birds, beetles, cats, and other people, all on the common ground of spirit. You participate simply by being alive. There's no choice in the matter - as long as you're alive.
What distinguishes humanity from other participants is that we are emotional beings. Our awareness, anticipation, and activity are all fueled by our emotions. Every conflict is, at the core, an emotional conflict. Every human progress is, at the core, an emotional progress.
Everything we do and all that we are is tied up with our emotions.
Jesus didn't reveal a personal God. Instead, he revealed and demonstrated an emotional being who was fully aware of his spiritual participation, without any separation between the two. We receive a personal God because we are emotional.
Emotionality demands meaning.
And all meaning that has ever been observed and practiced in humanity is a result of the emotional demand to name something. It is 'instinctual' for us to name a thing and give it meaning.
God becomes father, becomes provider, becomes savior, becomes lord, becomes counselor, and ultimately becomes the personal God, because that is the basis by which we interact with the divine.
It is impossible for humanity, as emotional beings, to interact with God purely as God. Doing so would necessarily strip us of our emotionality and erase what it means to be human. Instead, our potential is in there being no split between spirituality and emotionality. In other words, we can remain emotional beings while being fully aware of spiritual participation, without any separation between the two.
But there's a problem.
We often attach ourselves to whatever meaning we've derived from a thing. When that value is lost, abused, non-existent, or otherwise perverted, our emotionality becomes intangled within itself. It becomes self-focused and naturally destructive. We fall from an awareness of unity with the divine. We then perpetuate the fallen state. We teach it to our children, enforce it in our workplaces, and protect it to our deaths.
But there's a solution.
The Christian message points to a personal God who is father. The father loves unconditionally and without end in spite of the naturally destructive emotionality of who we are. Love is the framework for rebuilding the awareness. Grace is the contents of such a framework. Faith is trusting in the possibility of reunion. Hope is the confidence to regain awareness, whereby we devote our entire self toward reunification.
It's because of God's love for us that we're able to participate in him (grace), fully aware (hope) and without separation (faith).
The problem is solved by grace, through faith, with hope, because of love. The doctrine of human spirit dissolves in the face this answer.