Legge's translation of this line reads that the first nine, undivided, shows its subject returning and pursuing his own course, asking directly what mistake he should fall into, and answering that there will be good fortune. His brief commentary on the small image adds only that returning to pursue one's own course is right, and that good fortune follows from exactly that.
The line stands at the very base of Qian, the lower trigram of Small Taming, and a firm, undivided line in this lowest and odd numbered place counts as correctly seated. Xiao Xu as a whole turns on a single yielding line, the fourth, holding back the creative strength of the five yang lines beneath and around it, but at the first line that restraint has not yet been felt in any way that could divert its course. The image is of someone who had begun to stray, or who might have strayed, and instead turns back to a path that is genuinely his own, not one borrowed from another's ambition or imposed from outside.
Read against the structure of the hexagram, this earliest line explains why Small Taming opens so mildly. Heaven's own motion has not yet reached the wind above that will eventually check it, so a plain return to one's proper conduct meets no obstacle and draws no blame, and Legge's commentary treats that recovered course as the whole ground of the good fortune the line promises.