Part of how we’re wired up as humans is that we are meaning-making machines. And part of how we create meaning in life is identifying with religion, God or a Higher Power.
Me, I avoid using the word spiritual or divine to describe myself. I guess I subscribe to the idea that if someone speaks of him/herself in that way that they are big-noting** themselves. Also, I’m not sure what those words mean to me.
I can relate to the notion of sacredness, though, regarding: the Planet, Nature, the Yoga Shed, wildlife, certain relationships…even abstract concepts like trust.
When I first came across Sutra: II-45 on Ishvarapranidhana –  a word which is often translated as surrender to God – I felt myself getting tripped up and back-pedalling. I looked around for alternative explanations in much the same way patients will look around for a second or third opinion if they don’t like their doctor’s diagnosis.
Considering the thousands of translations and commentaries that have been written on the Sutra, it wasn’t hard to find a more secular description. These two in particular have been helpful:

…we can practice ishvarapranidhana…by putting aside some time each day, even a few minutes to avail ourselves of an intelligence larger than our own.
By setting aside enough time to get quiet and clear, we can begin to differentiate between the cluttered thoughts of our ordinary mind and the resonant intelligence that comes through as intuition. Rather than trying to unravel the mystery, we start to embody the mystery of life. – From Donna Farhi, Yoga Mind, Body & Spirit
And,  from Chip Hartranft – As we sit in stillness, pranidhana is a surrender that we can make in every moment – to let nature unfold exactly as it will, without our attachment or aversion – thereby entering the perspective of pure awareness. Isvara-pranidhana provides the point of focus to which the yogi continually returns in the course of practice…and the inspiration to cultivate non reaction….*
Samadi-siddhih-Isvara-pranidhanat

Through orientation toward the idea of pure awareness, one can achieve integration.*
*The Yoga-Sutra of Patanjali, a new translation with commentary by Chip Hartranft.
**(For those of you not from Down Under, ‘big-noting’ is a kind of boasting.)