Both Uses

heed
in
The Prophet, by Kahlil Gibran
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And for that wrong committed must you knock and wait a while unheeded at the gate of the blessed.†

unheeded = ignored

standard prefix: The prefix "un-" in unheeded means not and reverses the meaning of heeded. This is the same pattern you see in words like unhappy, unknown, and unlucky.
It is a flame spirit in you ever gathering more of itself, While you, heedless of its expansion, bewail the withering of your days.
*

heedless = ignorant (not paying attention to)

standard suffix: The suffix "-less" in heedless means without. This is the same pattern you see in words like fearless, homeless, and endless.

Definitions:

(1) (heed)
pay close attention to; or to do what is suggested -- especially with regard to a warning or other advice
(2) (meaning too rare to warrant focus)