The second line raises a question the first never had to face: what happens to modesty once other people notice it. Legge's translation describes humility that has made itself recognised, and attaches good fortune to firm correctness rather than to the recognition. The phrasing is careful. The humility does the making known, not its subject, which is the difference between a quality that has become visible through conduct and one that has been advertised.
Centrally placed in the lower trigram Gen, a yielding stroke in an even position, this line is correct by every standard the system applies, and its centrality is what allows the recognition to be harmless. Modesty at the edge of a trigram can tip into either self effacement or display. Held at the centre, it simply is what it is, and the notice it attracts does not alter it, because nothing about it was arranged for an audience in the first place.
The condition attached to the good fortune matters as much as the promise. Firm correctness is the guard against the one real danger of this position, which is that being known for humility becomes a reputation worth maintaining, at which point the humility has quietly turned into its opposite. The line does not ask its subject to hide. It asks that what is seen continue to be what is actually there.