What is the meaning of Allah Almighty’s saying: "And know that Allah intervenes between a man and his heart" (Al-Anfal/24)?

The verse is to be taken literally. Allah disposes of His servants, granting some success in faith and guiding them to Islam, while placing constriction and difficulty in the hearts of others, preventing them from Islam. He intervenes between a person and his heart, as stated in His exalted words: (So whoever Allah wishes to guide, He expands his breast to Islam; and whoever He wishes to misguide, He makes his breast tight and constricted as though he were ascending into the sky.) So, Allah disposes of His servants as He wills, expanding the hearts of some for faith and guiding them, while others are not granted such success.