The previous verses referred to Jews who adhered to their disbelief and obstinately continued practising what was blame-worthy. The present verse now cites those who were, no doubt, from among the People of the Book, but, when the Holy Prophet ﷺ came with his mission and they found in him, fully and unmistakably, all qualities the Last among Prophets was supposed to have according to the prophesies of their Scriptures, they believed in him - like Sayyidna ` Abdullah ibn Salam, Usayd and Tha'labah, may Allah be pleased with them all. The words of praise in this verse are for these blessed souls.
Commentary
The great reward promised to those referred to here is because of their qualities of faith and righteous deeds. As far as salvation as such is concerned that depends on the correction of essentials of doctrinal matters - of course, subject to the condition, that one's life ends with the blessing of faith ('Iman).