How sound are the two sayings: "Whoever abandons something for the sake of Allah, Allah will compensate him with something better than it," and "Whoever desires this world, let him adhere to the Quran; and whoever desires the Hereafter, let him adhere to the Quran"? And how does one act upon them?

The saying "Whoever leaves something for the sake of Allah, Allah will compensate him with something better" is not a hadith, but its meaning is sound and is supported by the hadith: "Indeed, you will not abandon anything for the sake of Allah, the Mighty and Majestic, except that Allah will replace it with something better for you." This meaning can be put into practice by overcoming desires and the soul's inclinations for the pleasure of Allah, abandoning what Allah has forbidden, and even abandoning what is permissible if it leads to Allah's pleasure. And the saying "Whoever desires the worldly life, let him resort to the Qur'an; and whoever desires the Hereafter, let him resort to the Qur'an" is not a hadith. The correct version, as narrated from Imam Al-Shafi'i, is: "Whoever desires the worldly life, let him resort to knowledge; and whoever desires the Hereafter, let him resort to knowledge." Attention to the Qur'an involves learning it, memorizing it, teaching it, contemplating its meanings, and acting upon it.