As he got older, the boy would have one main image of his father in his memory
The boy was woken up by a light late one night
He wasn't really awake and it looked like his dad was holding fire
It was really just because he'd lit a match to check on his son
But he held his hand curved around the match and the light was his love
And the curve of the hands looked like a heart
So his son felt like his dad had revealed his real heart
And the love there was too powerful to bear
On his dad's face, the love was too intense -- it was best seen when half awake in the night
It only lasted for a moment
But the son knew it was there forever after
I think that any paraphrasing of a poem comes down to what the reader feels about it. In reading this poem, you might want to ask a couple of questions that could help you determine what the meaning of this poem is to you. The first would be to discuss the relationship held by the father and son? Is there love present? If so, it is openly demonstrative, or one that is a bit difficult to express? Do both know how the other feels about them? (Keep in mind that the poem is constructed in a series of rhyming couplets, so as one line is spoken, its counterpart is heard afterwards.) Another set of questions to ask is about the nature of the title. Under what conditions might love be seen as a secret, or something that can only be understood by two people? The reality is that in paraphrasing the poem, it has to be done by you. It seems artificial for anyone to give you a line by line paraphrase because that is what the poem means to them and if you have to paraphrase it, the best one can do is to give a series of guiding questions upon which there can be reflection as you read it.
When paraphrasing a poem, one needs to look at the words and determine two things: What the author intended them to mean and what one sees for oneself in the words. For example, in the first stanza we are told that the scene is not going to be in the present.
"Across the years he could recall
His father one way best of all."
The person is now grown and remembering his father. He has one particular memory that he likes to look back upon.
"In the stillest hour of night
The boy awakened to a light."
He is now thinking back when he was a boy and there is a light in his room which caused him to wake up.
"Half in dreams, he saw his sire
With his great hands full of fire."
The child is not fully awake so it looks to him like his father's hands are aflame or filled with something burning.
"The man had struck a match to see
If his son slept peacefully."
His father had come in to check on his son, but the room was dark. Not wanting to wake the child, his father lit a match that would create just enough light to illuminate the child' face.
If you take each stanza and read through them, you will be able to create your own words to tell what each line says.