John Gill Commentary Nehemiah 9:8

"and foundest his heart faithful before thee, and madest a covenant with him to give the land of the Canaanite, the Hittite, the Amorite, and the Perizzite, and the Jebusite, and the Girgashite, to give it unto his seed, and hast performed thy words; for thou art righteous." — Nehemiah 9:8 (ASV)

And foundest his heart faithful before thee
A true believer in his word and promises, (Genesis 15:6) and closely attached to the fear of him, and observance of his commands, as abundantly appeared in the trial of him, in offering up his son, (Genesis 22:1Genesis 22:2Genesis 22:12) ,

and madest a covenant with him, to give the land of the Canaanites,
the Hittites, the Amorites, and the Perizzites, and the Jebusites,
and the Girgashites, to give it, [I say], to his seed ;
not to him personally, but to his posterity, at least including and chiefly designing them; of which covenant see (Genesis 15:18–21) ,

and hast performed thy words ,
for you are righteous; in all his ways and works, faithful to his promise, a covenant keeping God, and who kept and fulfilled this covenant, assisting Joshua to conquer the land of Canaan, and put Israel into the possession of it.