Rashi, on Isa 55:11

“So shall my word be, which shall go forth from my mouth: it shall not return to me void, but it shall do whatsoever I please, and shall prosper in the things for which I sent it.”

“so shall be My word that emanates from My mouth to inform you through the prophets, will not return empty, but will do good to you if you heed them.”

Imported from an open dataset — not yet checked against the printed edition.