Allāh keeps firm those who believe, with the firm word,1 in worldly life and in the Hereafter.2 And Allāh sends astray the wrongdoers. And Allāh does what He wills.
Translation: Saheeh International (English)
1 The testimony that there is no deity except Allāh and that Muḥammad (ﷺ) is the messenger of Allāh.
2 When questioned in their graves by the angels after death.
Through the monotheistic word, Allah makes the believers firm in their belief in the world until they die upon belief, as well as in the Transitory Stage in their graves when they are asked, and He will make them firm on the Day of Judgment. By causing them to associate partners with Him and disbelieve in Him, Allah will lead the wrongdoers away from guidance and what is correct. Allah does as He wishes when it comes to leading astray whomever He wants in accordance with His justice and guiding whomever He wants in accordance with His grace. Allah cannot be coerced (may He be glorified).