"Then whoever fears" means: knows "from a testator any bias or sin." Al-janaf (bias) is that he bequeaths with injustice while not intending the injustice, and al-ithm (sin) is that he bequeaths with injustice while knowing that. "Then he sets things right between them," meaning: between the beneficiary and the heirs, "then there is no sin upon him."
Muhammad said: Al-janaf in the speech of the Arabs is the deviation from the truth; it is said of it: janafa, yajnafu.
﴿فَمن خَافَ﴾ يَعْنِي: علم ﴿مِنْ مُوصٍ جَنَفًا أَو إِثْمًا﴾ الجنف: أَن يُوصي بجور؛ وَهُوَ لَا يتَعَمَّد الْجور، وَالْإِثْم: أَن يُوصي بجور وَهُوَ يعلم ذَلِك ﴿فَأصْلح بَينهم﴾ يَعْنِي: بَين الموصَى لَهُ وَالْوَرَثَة ﴿فَلَا إِثْم عَلَيْهِ﴾
قَالَ مُحَمَّد: الجنف فِي كَلَام الْعَرَب: الْميل عَنِ الْحق؛ يُقَال مِنْهُ: جنف يجنف.