At the root of Rav Kook's teaching stands the image of a single life-force that flows from the divine source and enlivens all of existence: Otzrot HaRaayah (Volume 6, Part א 37:18) speaks of light and life that pour from the infinite divine light — one in which existence and perfection are inseparable within the divine sphere and its manifestations — as it comes to vivify all the worlds, existence in its totality, and in particular all living, sentient beings.
This animating current is not external to the soul's faculties but is their very substance: Shemonah Kevatzim 5:82 describes how the eye's sight and the ear's hearing do not draw their light from their own particular source, but rather from that same illumination of life that flows from the light of the soul to enliven the entire body — and when that force bursts forth at the point most suited to its expression, it emerges as actual seeing and actual hearing.
As the holy light spreads, it consecrates not only inner faculties but the entire range of a person's perceptions and possessions: Shemonah Kevatzim 6:136 traces how the light of holiness first spreads over the power of speech, making it entirely a wellspring of sacred life, then elevates hearing so that all that is heard joins a great, pure, and holy light, then spreads to sight so that every seeing is sanctified and clarified — and ultimately reaches every movement, every feeling, and even all of one's belongings, one's staff and one's donkey and all that one has.
The thread connecting the divine heights to concrete reality gathers all things into itself: Shemonah Kevatzim 7:8 teaches that the more souls draw from the source of holiness and ascend, the more everything ascends with them — bodies, their forces, their instruments and character — and the worlds in all their materiality are refined through them, while the cord drawn from the heights of holiness, when properly aligned, gathers into itself all the practical contents of life, all living creatures, all the worlds, and all the aspirations of souls both collective and individual.
This understanding of life-force also has a cosmic-unifying dimension: Ein Aya (Berakhot 5:70) explains that the power of life is the unification of all particular limbs and parts of the body around a single center governed by the intellect, and that the ultimate perfection of all existence is likewise that all its parts be unified through the light of God — so that all scattered portions of humanity are bound together into one holy center, all ultimately cleaving to the living God.
The holy light does not flee matter but demands that the world bring forth the refinement and health latent within natural life: Shemonah Kevatzim 2:309 describes holiness itself — the light of the world that stands above nature — as demanding from the world, and from Israel especially, the purification and normality of natural life in feeling, intellect, and sensation, with great divine illuminations revealing the secrets stored in the darkness.
The vocation of people of deep heart is precisely to uncover this spiritual wellspring: Shemonah Kevatzim 4:133 calls their sacred work the constant, unceasing exposure of the spiritual spring, feeling inwardly and revealing to others the splendor and majesty, the strength and the firmly-built being of the life of Atzilut, whose source of life is the holy light clinging to the highest love — love of God — in the brilliance of its purity and the power of its light.
Even the divine attribute of truth is revealed as itself a life-force filling all worlds: Shemonah Kevatzim 8:201 teaches that from within us arises the living knowledge of how truth and necessity are genuinely unified at their foundation, and that the divine delight in the revelation of truth's light, together with truth's own power of certainty, is in reality one single matter — expressed in many different registers only through verbal presentation — whose many hues fill all the worlds with eternal strength and splendor.
All words, deeds, and movements share in this downward-flowing divine life: Otzrot HaRaayah (Volume 6, Part א 37:5) draws the parallel that just as speech flows from a supernal source through its material and spiritual waves until it reaches human utterance, so too deeds and movements in general issue from a supernal place and flow until they are revealed in action — and their power can be recognized in this world through the mitzvot, which are filled with the splendor of holiness of the Eternal Life, while in the future the force of life and light will be revealed in all the movements across the full breadth of the land.
The upper world receives and transmits these divine vitalities to sustain all lower existence: תורת חיים (משפטים 7) teaches that the supernal Eretz HaChayim receives all lights and vitalities from Atzilut and transmits them downward to sustain all worlds, analogous to how physical earth produces sustenance for all living creatures through the divine power of growth planted within it, without which no creature could exist even for a moment.