The Quran

وَالَّذينَ آمَنوا وَاتَّبَعَتهُم ذُرِّيَّتُهُم بِإيمانٍ أَلحَقنا بِهِم ذُرِّيَّتَهُم وَما أَلَتناهُم مِن عَمَلِهِم مِن شَيءٍ ۚ كُلُّ امرِئٍ بِما كَسَبَ رَهينٌ

Ali Unal

Those who have believed and their offspring have followed them in faith, We will unite them with their offspring (even though the faith of the latter may not be of the same degree as that of the former), and We will not decrease the reward of their deeds in anything (because of their being united with their offspring). Every person will enjoy according to what he has earned.¹

God will unite the parents with their believing offspring in Paradise, even though the faith and deeds of their offspring may not be of the same rank as them. This will be another blessing for the believers. However, everyone will not enjoy Paradise to the same degree, even though they will be together in the same place. Each person will enjoy it according to the degree of their own faith and deeds.
The verse also hints that, as pointed out in 56: 10–14, particularly at the beginning of a new movement of faith, those who attain the faith first are generally more valued in God’s sight and will be the foremost in enjoying Paradise. They have outstripped others in believing and supported God’s cause at a time when supporting it was the most difficult, without considering any worldly advantage, and, therefore, suffered greater hardships than those who followed.