Nearby ayahs help place verse 29:8 in sequence and meaning.
وَمَن جَـٰهَدَ فَإِنَّمَا يُجَـٰهِدُ لِنَفْسِهِۦٓ ۚ إِنَّ ٱللَّهَ لَغَنِىٌّ عَنِ ٱلْعَـٰلَمِينَ
And whoever strives only strives for [the benefit of] himself. Indeed, Allah is free from need of the worlds.
وَٱلَّذِينَ ءَامَنُوا۟ وَعَمِلُوا۟ ٱلصَّـٰلِحَـٰتِ لَنُكَفِّرَنَّ عَنْهُمْ سَيِّـَٔاتِهِمْ وَلَنَجْزِيَنَّهُمْ أَحْسَنَ ٱلَّذِى كَانُوا۟ يَعْمَلُونَ
And those who believe and do righteous deeds - We will surely remove from them their misdeeds and will surely reward them according to the best of what they used to do.
وَٱلَّذِينَ ءَامَنُوا۟ وَعَمِلُوا۟ ٱلصَّـٰلِحَـٰتِ لَنُدْخِلَنَّهُمْ فِى ٱلصَّـٰلِحِينَ
And those who believe and do righteous deeds - We will surely admit them among the righteous [into Paradise].
وَمِنَ ٱلنَّاسِ مَن يَقُولُ ءَامَنَّا بِٱللَّهِ فَإِذَآ أُوذِىَ فِى ٱللَّهِ جَعَلَ فِتْنَةَ ٱلنَّاسِ كَعَذَابِ ٱللَّهِ وَلَئِن جَآءَ نَصْرٌ مِّن رَّبِّكَ لَيَقُولُنَّ إِنَّا كُنَّا مَعَكُمْ ۚ أَوَلَيْسَ ٱللَّهُ بِأَعْلَمَ بِمَا فِى صُدُورِ ٱلْعَـٰلَمِينَ
And of the people are some who say, "We believe in Allah," but when one [of them] is harmed for [the cause of] Allah, they consider the trial of the people as [if it were] the punishment of Allah. But if victory comes from your Lord, they say, "Indeed, We were with you." Is not Allah most knowing of what is within the breasts of all creatures?