The message of "On Children" from The Prophet by Kahlil Gibran focuses on the idea that children are their own people. The implications of this idea lead the speaker to advise against indoctrinating children and to advise against parental attempts at shaping the child to be like the parent.
"You may give them your love but not your thoughts,
For they have their own thoughts."
The message is one that advocates being supportive of children through love, shelter and strength. Also, the poem implies (and promotes) the idea that individuality is part of the way that (1) children come to exist fully as the most valuable version of themselves and (2) children exist as part of a larger (mystically imbued) world or, as the poem puts it, "Life."
"Your children are not your children.
They are the sons and daughter's of Life's longing for itself."
This metaphysical vision of the individual's relationship to life and to the world is central to the larger text of The Prophet and is fully part of the book's nature as a wisdom text. While there may be some debate as to whether or not a relatively contemporary work like Gibran's was intended to be a wisdom text, it does bear many of the characteristics of texts of this kind.
Offering an extensive articulation of a world-view that encompasses philosophical perspectives on the nature of being and also metaphysically inflected yet actionable approaches to social institutions like marriage and parenting, The Prophet takes on the character very much akin to Thus Spake Zarathustra and The Republic as well as The Bhagavad Gita and The Torah.
As in these renowned works of philosophy and religion, The Prophet "focuses on human relationships—with others, with nature, and with God" (eNotes).
The intended audience for such works is hard to define in narrow terms as these texts seem to appeal to philosophical seekers of all sorts. They appeal to a very general audience as well. We might narrow this poem's audience down somewhat by identifying its advice for parents, yet the poem's overall message about an individual's relationship to those around him or her remains quite broad.
The tone of this poem, like others in the book, is prophetic, exhortative and highly rhetorical. The poem reads, largely, like a speech.