The fifth line of Increase (King Wen 42) is drawn as yang, the numeral nine in the old divination manuals. James Legge's translation renders the line as sincere heart seeking to benefit those below, no need even to ask about it, great good fortune, and they respond with sincere hearts to acknowledge his goodness. The image sits inside a hexagram whose judgment as a whole concerns advantage in every movement undertaken, even advantage in crossing the great stream, and this line supplies one stage of that larger reading rather than a complete statement on its own.
Structurally the line stands at the middle place of the upper trigram Xun, wind in Legge's readings of the eight trigrams, while the lower trigram of the hexagram is Zhen, thunder in the same traditional set of images. The Great Symbolism of the hexagram reads wind and thunder together; the superior man, seeing what is good, moves toward it, and seeing his errors, turns away from them, and the fifth line takes its place inside that combined picture of Zhen below and Xun above.
Read on its own the line neither opens nor closes the hexagram's argument. It marks the point where Xun is either forming (in the lower trigram) or completing itself (in the upper), and later interpreters treat its image, The Sincere Heart Seeking to Benefit Those Below, as the concrete case through which the hexagram's abstract judgment becomes visible in a single situation rather than a general principle.