What exactly is the difference of meaning between saddan and suddan in Qur'an verse 36:9?

In Surah Yaseen, verse 36:9, the terms "saddan" and "suddan" are part of the phrase describing barriers placed before and behind those who are misled. The verse states: And We have set a bar before them and a bar behind them, and (thus) have covered them so that they see not. 36:9.

The term "saddan" refers to a barrier or obstruction, indicating a physical or metaphorical blockage that prevents individuals from seeing or understanding the truth. This term emphasizes the concept of a hindrance that obstructs one’s ability to receive guidance.

On the other hand, "suddan," derived from the same root, accentuates the idea of being covered or veiled. This suggests a deeper level of incapacity, where not only are the individuals obstructed from the truth, but their perception is also dulled, preventing them from even recognizing the barriers in their way.

Tafsir Ibn Kathir explains that these barriers symbolize the heavy restraints on those who are distant from guidance, portraying them as being bound and unable to turn towards benefit or truth. This metaphorical imagery reinforces the concept that their hearts and eyes are sealed, preventing them from responding to the divine message.

Thus, while both terms convey the idea of obstruction, "saddan" focuses on the existence of barriers, whereas "suddan" implies a more profound inability to perceive or acknowledge the truth due to the veils placed over their understanding.