Nine in the Fourth Place, during a time of Opposition, occupies an uneasy position: having no partner and trapped between two yin lines, it is estranged and dwells in isolation.
Endowed with the virtue of firm yang in a time of estrangement, standing alone without allies, it must seek out and unite with its kind; thus it 'meets a primal husband'. Fū refers to yang; 'primal' means good.
Initial Nine, at the beginning of Opposition, is able to associate with someone of like virtue and dispel the regret of estrangement; it is the most excellent at managing Opposition. Therefore it is designated a 'primal husband', which is like saying an excellent gentleman.
The Fourth has passed the center, its estrangement having become excessive, not matching the excellence of the First. The Fourth and the First both dwell at the base of their respective trigrams as yang lines, occupying positions that would otherwise correspond.
In a time of estrangement, each lacks an ally, so naturally they draw close through shared virtue and meet. When those of like virtue meet, they must treat each other with utmost sincerity; 'mutual trust' means each possesses sincere trust.
When the two yangs above and below unite with utmost sincerity, what time could they not act in? What danger could they not overcome? Therefore, though dwelling in danger, there is no blame.
In a time of Opposition, dwelling alone between two yin lines in an improper position brings peril and blame; but because it meets a primal husband and maintains mutual trust, it manages to avoid blame.