I Chronicles 16:15 Midrash

זִכְר֤וּ לְעוֹלָם֙ בְּרִית֔וֹ דָּבָ֥ר צִוָּ֖ה לְאֶ֥לֶף דּֽוֹר׃

Remember His covenant for ever, The word which He commanded to a thousand generations;