He that walketh uprightly, and worketh righteousness. An upright walk is the first requisite (comp. Genesis 17:1; Psalms 26:3, Psalms 26:11; Isaiah 33:15). Such a walk involves the doing of righteousness, not, of course, in absolute perfection, but with a sincere intention, and so as to have "the answer of a good conscience towards God" (1 Peter 3:21).
And speaketh the truth in his heart. Not "from his heart," as in the Prayer-book Version, which would make the reference one to mere truth of speech, but "in his heart," which points to internal truthfulness—that truthfulness "in the hidden council-chamber of the soul," which "holds no parley with what is false" (Kay).