His saying: "O mankind, indeed you are exerting yourself towards your Lord with exertion," meaning: working towards your Lord with an action. "And you will meet Him," meaning: you will encounter the reward for that action; if it is good, then it is good, and if it is evil, then it is evil.
Muhammad said: "Al-kadh" (exertion) in the language means: striving and persistent, diligent work in the affairs of this world and in the affairs of the hereafter. The response to "when" is indicated by "and you will meet Him." The meaning is: when the Day of Resurrection occurs, man shall encounter his deeds.
قَوْله: ﴿يَا أَيهَا الإِنْسَانُ إِنَّكَ كَادِحٌ إِلَى رَبِّكَ كدحا﴾ أَيْ: عَامِلٌ إِلَى رَبِّكَ عَمَلًا ﴿فملاقيه﴾ فَمُلاقٍ ثَوَابَ ذَلِكَ الْعَمَلِ، إِنْ خَيْرًا فَخَيْرٌ، وَإِنْ شَرًّا فَشَرٌّ.
قَالَ مُحَمَّدٌ: الْكَدْحُ فِي اللُّغَةِ: السَّعْيُ وَالدُّءُوبُ فِي الْعَمَلِ فِي بَابِ الدُّنْيَا وَفِي بَابِ الْآخِرَةِ. وَجَوَابُ (إِذَا) يَدُلُّ عَلَيْهِ فَمُلاقِيهِ، الْمَعْنَى: إِذَا كَانَ يَوْمُ الْقِيَامَةِ لَقِي الْإِنْسَان عمله.
