Translation:

31. But any of you that is devout in the service of Allah and His Apostle and works righteousness to her shall We grant her reward twice: and We have prepared for her a generous Sustenance.

Notes (Tafseer)

3710. Twice, i.e., once as a righteous woman, and again as a Mother of the Believers, serving the believing women and thus showing her devotion to Allah and His Apostle.

3711. Sustenance: all that is necessary to sustain her in happiness in her future life.