Swami Vivekananda in June 1895 took classes for a small group of 12 disciples in Long Island, NY.  This is where he shared some of his best lectures, and one of the days in full flow he composed the Song of Sannyasin.  In my understanding, a sannyasin is someone who renounces, and not necessarily someone who wears Ochre.

Sharing his profound composition (followed by a short commentary on the meaning), on this day of remembering Swami Vivekananda.

The Song of the Sannyasin

Wake up the note! the song that had its birth
Far off, where worldly taint could never reach,
In mountain caves and glades of forest deep,
Whose calm no sigh for lust or wealth or fame
Could ever dare to break; where rolled the stream
Of knowledge, truth, and bliss that follows both.
Sing high that note, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Strike off thy fetters! Bonds that bind thee down,
Of shining gold, or darker, baser ore ;
Love, hate—good, bad—and all the dual throng,
Knowthe , slave is slave, caressed or whipped, not free ;
For fetters, though of gold, are not less strong to bind ;
Then off with them, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Let darkness go; the will-o’-the-wisp that leads
With blinking light to pile more gloom on gloom.
This thirst for life foreverer quench ; it drags
From birth to death, and death to birth, the soul.
He conquers all who conquerrs self. Know this
And never yield, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

“Who sows must reap,” they say, “and cause must bring
The sure effect ; good, good ; bad, bad ; and none
Escape the law. But whoso wears a form
Must wear the chain.” Too true ; but far beyond
Both name and form is Âtman, ever free.
Know thou art That, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

They know not truth who dream such vacant dreams
As father, mother, children, wife, and friend.
The sexless Self! whose father He? whose child?
Whose friend, whose foe is He who is but One?
The Self is all in all, none else exists ;
And thou art That, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

There is but One—The Free—The Knower—Self!
Without a name, without a form or stain.
In Him is Mâyâ dreaming all this dream.
The witness, He appears as nature, soul.
Know thou art That, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Where seekest thou? That freedom, friend, this world
Nor that can give. In books and temples vain
Thy search. Thine only is the hand that holds
The rope that drags thee on. Then cease lament,
Let go thy hold, Sannyâsin bold! Say —
“Om Tat Sat, Om!”

Say, “Peace to all: From me no danger be
To aught that lives. In those that dwell on high,
In those that lowly creep, I am the Self in all!
All life both here and there, do I renounce,
All heavens and earths and hells, all hopes and fears.”
Thus cut thy bonds, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Heed then no more how body lives or goes,
Its task is done. Let Karma float it down ;
Let one put garlands on, another kick
This frame ; say naught. No praise or blame can be
Where praiser praised, and blamer blamed are one.
Thus be thou calm, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Truth never comes where lust and fame and greed
Of gain reside. No man who thinks of woman
As his wife can ever perfect be ;
Nor he who owns the least of things, nor he
Whom anger chains, can ever pass thro’ Maya’s gates.
So, give these up, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Have thou no home. What home can hold thee, friend?
The sky thy roof, the grass thy bed; and food
What chance may bring, well cooked or ill, judge not.
No food or drink can taint that noble Self
Which knows Itself. Like rolling river free
Thou ever be, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Few only know the truth. The rest will hate
And laugh at thee, great one ; but pay no heed.
Go thou, the free, from place to place, and help
Them out of darkness, Maya’s veil. Without
The fear of pain or search for pleasure, go
Beyond them both, Sannyâsin bold! Say—
“Om Tat Sat, Om!”

Thus, day by day, till Karma’s powers spent
Release the soul for ever. No more is birth,
Nor I, nor thou, nor God, nor man. The “I”
Has All become, the All is “I” and Bliss.
Know thou art That, Sannyâsin bold! Say —
“Om Tat Sat, Om!”

A short commentary on the poem 

Fetters may be of gold, or of darker iron, but they are still fetters. In the beginning, one takes up service to purify oneself, and has discipline for practices, and at some stage one has to go beyond them.  A slave is a slave whether kept in comforts or whether in harsh conditions. 
Be bold Sanyasi and say Om Tat Sat, Om

He conquers all who conquers self, and the thirst to live drags us down and makes us take rebirth. 

The karmic law holds, and you shall reap what you sow, but one needs to escape the law. You are beyond name and form as Atman, and recognize thyself to be that.  As anyone recognizes with form will be bound. Be bold Sanyasi and say Om Tat Sat, Om

There is only one Self in all, and none else exists. Recognize that. This Self is without name, form, and is Free.
Why are you seeking freedom in this world that they cant give? In books, and temples your search is vain. You only are holding on to the rope that is dragging you deeper into the world. Let go of the hold. Be bold Sanyasi and say Om Tat Sat, Om

Be peaceful to all creatures, included those lowly creeps as Self lives in all.  Renounce on heaven, earth, and hell, and all hopes and fears. Renounce all the pleasures and fear, and the duality. Be bold Sanyasi and say Om Tat Sat, Om

Don’t be overly attached to how the body lives, and also how anyone treats you – either with garland or gives you a kick.  Be calm in both whether praised or blamed. Be bold Sanyasi and say Om Tat Sat, Om

If you have lust or greed or desire fame,  the Truth will never come to you. If you are attached to things, or in whom anger lives, you can’t pass through the maya’s (illusions) gates.  So give these up, and be a bold Sannyasi and say Om Tat Sat, Om

The sky is your roof, the grass your bed, and the food whatever chance/lord gives you – well cooked or not, don’t judge, and be thankful.  No food or drink can taint the Self. Like a free-flowing river, is your true Self. Bold Sannyasi say Om Tat Sat, Om.

Only a few know the truth, and many will laugh and the rest will hate. But don’t pay any attention, and go from place to place and help your fellows get out of darkness and from the veil of Maya. Without the fear of pain or attraction of pleasure, go beyond both, bold Sannyasin, chant Om Tat Sat, Om.

Thus day by day, your Karma will dissolve your soul will be released and there is no more birth, no I, no thou, no God, no man.   You will realize that I has become All, and that All is “I”. Know Thou Art That.  Bold Sannyasi, chat Om Tat Sat Om. 

Listen to this sung by a devotee below 

Source : Complete Works of Swami Vivekanand, Vol 4