(Will they not then reflect upon the Qur'an, or are there locks upon their hearts) means, there indeed are locks upon some hearts, firmly closing them so that none of its meanings can reach them. Ibn Jarir recorded from Hisham bin `Urwah, from his father, may Allah be pleased with him, that Allah's Messenger ﷺ once recited this Ayah,
(Will they not then reflect upon the Qur'an, or are there locks upon their hearts) and a young man from Yemen said, "Indeed, there are locks upon them -- until Allah opens them totally or slightly." After that `Umar, may Allah be pleased with him, always liked that young man, and kept that to himself until he became in charge, upon which he utilized him (as a consultant).
الشَّيْطَانُ سَوَّلَ لَهُمْ وَأَمْلَىٰ لَهُمْ (it is Satan who has tempted them and involved them in far-fetched fancies. - 47:25). In this sentence, two acts have been ascribed to the devil: - taswil [ meaning the act of decking out evil works fair to some people, and imla' meaning the act of giving respite. First, he made their evil works look good and beautiful to them, and then prolonged their false hopes which will never be fulfilled.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 23–27
It is characteristic of a hypocrite to talk big. But his words do not follow his actions; he talks of jihad but in times of defensive battle runs away from it. It is the way of true people of faith that they are always ready to hear and obey and, when stringent measures are decided upon, they prove by their actions that they have fulfilled the pledge that they had taken before God as their witness. In order to avoid participation in defensive battle, hypocrites make a pretence of being lovers of peace. But, in reality, whenever they have the opportunity, they start spreading bad blood, so much so that, completely careless of Muslims who are their relatives, they become the supporters of their enemies. In the eyes of God, such people are accursed. Being such means their thinking power is taken away from them. In spite of having eyes, they will not see, and in spite of having ears, they will hear nothing.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.