"And one who invites to Allah, by His permission," meaning: by [His] revelation, "and an illuminating lamp," meaning: a light-giving one.
﴿وداعيا إِلَى الله بِإِذْنِهِ﴾ يَعْنِي: بِالْوَحْي ﴿وسراجا منيرا﴾ مضيئا