﴿ ٱلَّذِينَ لَا يُؤْتُونَ ٱلزَّكَوٰةَ وَهُم بِٱلْءَاخِرَةِ هُمْ كَٰفِرُونَ ﴾

“[and] those who do not spend in charity: for it is they, they who [thus] deny the truth of the life to come!”

who do not pay the alms and who are disbelievers in the Hereafter the repetition of hum ‘they’ is for emphasis.