I concluded, at length, that the mere speculative conviction that it was our interest to be completely virtuous, was not sufficient to prevent our slipping; and that the contrary habits must be broken, and good ones acquired and established, before we can have any dependence on a steady, uniform rectitude of conduct.
There are no more uses of "rectitude" in the book.
Show samples from other sources
Mr. Cunningham, a man of uncompromising rectitude, had given her a pint free of charge for having guessed his name yesterday, one of the tiny things she adored about Maycomb: people remembered their promises.
Harper Lee -- Go Set a Watchman
Now I sat down to write a different kind of letter, one that tried to convey how much she meant to me, how much she had taught me, how I wanted to emulate her rigor and rectitude, how much I loved her and missed her.