Tafsir of Al-Ma'idah 5:9

وعد الله الذين آمنوا وعملوا الصالحات لهم مغفرة

Allah has promised those who believe and do deeds of righteousness, that for them there is forgiveness (for their sins),

وأجر عظيم

and a great reward. which is Paradise, that is part of Allah's mercy for His servants. They will not earn Paradise on account of their good actions, but rather on account of His mercy and favor, even though they will qualify to earn this mercy on account of their good actions. Allah has made these actions the cause and path that lead to His mercy, favor, pardon and acceptance. Therefore, all this is from Allah Alone and all thanks are due to Him. Allah said next,

والذين كفروا وكذبوا باياتنا أوليك أصحاب الجحيم