"{So We have only made it easy}" meaning: the Quran, "{in your tongue}" O Muhammad, "{that you may give glad tidings with it to the righteous}" of Paradise, "{and warn with it}" against the Fire, "{a people who are obstinate}" meaning: those characterized by stubbornness and contentiousness; meaning: Quraysh.
﴿فَإِنَّمَا يسرناه﴾ يَعْنِي: الْقُرْآن ﴿بلسانك﴾ يَا مُحَمَّدُ ﴿لِتُبَشِّرَ بِهِ الْمُتَّقِينَ﴾ بِالْجنَّةِ ﴿وتنذر بِهِ﴾ بالنَّار ﴿قوما لدا﴾ أَيْ: ذَوِي لَدَدٍ وَخُصُومَةٍ؛ يَعْنِي: قُريْشًا