The lifelong dedication of this old teacher has given him a halo of sanctity.

halo 的意思是"光环、光晕"，原指宗教绘画中圣徒头部周围的光环，象征神圣或崇高。在比喻用法中，halo 表示某人因高尚品质或行为而获得的崇敬氛围。