Success produces confidence confidence relaxes industry, and negligence ruins the reputation which accuracy had raised.

The sentence sketches a moral-psychological chain: achievement breeds self-assurance; self-assurance can dull the disciplined effort (“industry”) that produced the achievement; and that slackening leads to carelessness, which in turn destroys the hard-won reputation built on “accuracy” (care, exactness, reliability). The warning is not against success itself but against the complacency it can induce. It also reflects an early modern emphasis on reputation as a fragile social asset, maintained by continual performance rather than past laurels. In effect, the quote argues that excellence must be sustained by ongoing vigilance, because the very feeling of security that comes with success can become the seed of decline.