Tafsir of An-Naml 27:71

They sought to hasten the promised punishment. It was said to them: {Perhaps there has followed you}—meaning, some of it has already overtaken you, which is the punishment on the Day of Badr.

The lam (in radifa lakum) is added for emphasis, similar to the ba in: {And do not throw [yourselves] with your hands [into destruction]} (Al-Baqarah: 195). Alternatively, it implies the meaning of a verb that takes the lam as a preposition, such as dana lakum (it has drawn near to you) or azafa lakum (it has approached you). Its meaning is: "It has followed you and overtaken you."

It has also been used with min (from), as the poet says: Then, when we followed (radafna) from Umayr and his companions, They turned away quickly, while death was galloping. Meaning: We drew near to Umayr.

Al-A‘raj read it as radafa lakum (with a fatha on the dal), while others read radifa (with a kasra). These are two dialects, though the kasra is more eloquent.

‘Asa (perhaps), la‘alla (maybe), and sawfa (will/soon), when used in the promises and threats of kings, indicate the truth and seriousness of the matter, leaving no room for doubt. By using such terms, they intend to display their dignity and composure, showing that they do not rush to take vengeance because they are confident in their power, their dominance, and their certainty that their enemy cannot escape them. A mere gesture from them is sufficient to achieve their objectives. Thus, the promises and threats of Allah follow this same manner.

{And indeed, your Lord is full of bounty to the people, but most of them do not show gratitude.}