The poem is stating, to stop and see what you have, take stock, before you neglect or lose “it”.
“A bird in the hand is worth more than two in a bush”!
I would say the answer is "harbor". This word is usually used as a noun; but in this case, it is a verb that means to provide shelter to someone or something, to keep someone safe, but also to have something in mind and think about it. This word is purposefully chosen and fits into Whitman's well-intended, philanthropic and inclusive worldview.
Jimmy is dependable and faithful
Explanation:
A formal email is an email used while conducting business with a new associate or executive, sending a professional inquiry, or corresponding about a job.