BEGINNING

When first the light broke through the primal darkness;
When first the sun arose upon the planet;
When first God made the innocence of Adam,
Or built the woman who would assuage man's heartache;
When first a sacrifice appeased His anger
Or when He saw the blood of the first martyr
God had in mind another kind of Manhood,
A greater Light to lighten all of mankind,
A brighter Sun to light a grander landscape ‑
A sinless Man, obedient to His Father,
A sorer Sufferer who trod a harsher pathway
Until He gave Himself ‑ the better ransom.

The form is somewhat of my invention. It is based on my, possibly defective, understanding of the Old French laisse. The general principles are:
each stanza had twelve lines;
all twelve lines assonate, i.e. the last stressed syllable has the same vowel sound - full rhymes are usually accidental;
the basic measure is the so-called iambic, unstressed syllable followed by stressed;
each line has five stresses and a break after the second or third stress;
in a substantial minority of lines there is an additional unstressed syllable after the break or at the end of the line, or both.

If these technical details are a distraction, forget them; if lack of them would distract, refer to them.