word - answering to “covenant” [Psa 105:9] in the parallel clause, namely, the word of promise, which, according to Psa 105:10, He set forth for an inviolable law.
commanded - or, “ordained” (Psa 68:28).
to a thousand generations - perpetually. A verbal allusion to Deu 7:9 (compare Exo 20:6).