Legge gives the fourth line as the fourth nine, undivided, showing its subject treading on the tail of a tiger, becoming full of apprehensive caution, so that in the end there is good fortune. This line steps onto the same ground the third line occupied, direct contact with the tiger's tail, yet reaches a wholly different outcome because of the caution its subject brings to the act.
Nine in the fourth place opens Qian, the upper trigram, directly above the boundary where the third line was bitten, and the line's good fortune depends entirely on the apprehension it feels rather than on any greater strength it possesses. Where the third line's subject overestimated their own capacity, the fourth line's subject treads the identical danger honestly aware of it, and that awareness, rather than removing the risk, is what allows the risk to be survived.
Legge's phrasing is deliberate in placing the caution before the good fortune, as if the sequence itself were the lesson, fear rightly felt at the moment of real danger is not weakness but the very thing that makes treading near the tiger survivable, in sharp contrast to the misjudged confidence the line immediately before it showed failing.