Hassan ibn Thabit was a great and a known Arab poet. He was hired by the Quraish leadership of Makkah to prepare a masterpiece to spread propaganda against the Last Messenger of God, Muhammad (peace be upon him).
Hassan thought that he should go and see this men in order to write his poem. When he saw the face of Prophet Muhammad, he accepted Islam, went back returned the money & wrote a poem (below) about the physical characteristics of Prophet Muhammad. After that he became the official poet of the Prophet and became the defender of the Prophet and of Islam against the propaganda by the people of Quraish.
When I saw his light shining forth,
In fear I covered my eyes with my palms,
Afraid for my sight because of the beauty of his form.
So I was scarcely able to look at him at all.
The lights from his light are drowned in his light
and his faces shines out like the sun and moon in one.
A spirit of light lodged in a body like the moon,
a mantle made up of brilliant shining stars.
I bore it until I could bear it no longer.
I found the taste of patience to be like bitter aloes.
I could find no remedy to bring me relief
other than delighting in the sight of the one I love.
Even if he had not brought any clear signs with him,
the sight of him would dispense with the need for them.
Muhammad is a human being but not like other human beings.
Rather he is a flawless diamond and the rest of mankind is just stones.
Blessings be on him so that perhaps Allah may have mercy on us
on that burning Day when the Fire is roaring forth its sparks.
—Hassan ibn Thabit
The defender of Muhammad & his message