Jesus Christ is the same yesterday and today and forever. [Hebrews 13:8]
Put in context, the author was encouraging the readers to remain strong in the faith, and not to revert to Judaism that denied Jesus as the Christ, because their Saviour was always the same and would be the same forever – He who had sustained His people (those before them), would also sustain them.
It is the same case for us. Christ whom those before us had put their faith in, will also help us just as He had helped them. His gospel is the same from everlasting to everlasting. Those people cited in chapter 11 were justified by faith, thus we and those after us would also be justified by faith.