لَهُ حَاجِبٌ عَنْ كُلِّ أَمْرٍ يَشِينُهُ
He has a protector against everything that would disgrace him.
وَلَيْسَ لَهُ عَنْ طَالِبِ الْعُرْفِ حَاجِبُ
Yet no barrier prevents a seeker of kindness from reaching him.
The first indefinite «حاجب» can magnify the protection enjoyed by the subject. The second, occurring under negation, emphasizes that no barrier keeps a seeker of favor away. The two uses need not have the same effect.
Honor and contempt are different contextual readings of indefinite expressions; neither should be inferred from the noun form alone.