2/88 — "Our hearts are wrapped"
غُلْف — root gh-l-f: a wrapping, a sheath. From the same root comes ghilāf (a case, a covering). Like the scabbard on a sword: the contents are protected but cannot be used.
This is not a confession but an excuse. What is said is: "your word does not work on us, because our heart is closed." Responsibility is taken from the person and loaded onto his constitution. Its present-day counterpart is more than familiar: "this is how I am", "it is not for me", "my nature is not suited to this".
The answer comes in two words: "bal" — no, it is not so. And the cause is reversed: they do not reject because the heart is closed; the heart has closed because they reject. The order we set up for the seal at the seventh verse of the sūra is confirmed once more here: the closing is the consequence of choice, not its cause.