"No falsehood comes to it," meaning: Iblis (Satan), "from before it or from behind it." This is the interpretation of al-Kalbi. "No falsehood comes to it from before it," meaning: from its past.
﴿لَا يَأْتِيهِ الْبَاطِل﴾ يَعْنِي: إِبْلِيس ﴿مِنْ بَيْنِ يَدَيْهِ وَلَا من خَلفه﴾ تَفْسِير الْكَلْبِيّ ﴿لَا يَأْتِيهِ من بَين يَدَيْهِ﴾ يَعْنِي: من قبل