He hath remembered his covenant forever - That is, God has had it constantly in remembrance, or always. Compare the notes at Luke 1:72. Though the covenant was made long since; though many generations of people have passed by; though great changes have occurred; though many calamities have come upon the nations, yet his ancient covenant and promise have never been forgotten. All his promises have been fulfilled; all ever will be. The “covenant” here referred to is that which was made with Abraham, and through him with the Hebrew people.
The word which he commanded - The thing which he commanded; that is, all which he ordained and appointed.
To a thousand generations - Very many generations; or, any number of generations: that is, always. Compare Exodus 20:6. The experience of the people through all the generations of their history has shown that in what he has promised and directed he is unchanging.