وَلَا نَذْكُرُهُمْ إِلَّا بِخَيْرٍ وَنَرَى حُبَّهُمْ دِينًا وَإِيمَانًا وَإِحْسَانًا وَبُغْضَهُمْ كُفْرًا وَنِفَاقًا وَطُغْيَانًا
We speak of the Companions only with goodness; we regard love for them as religion, faith and excellence, and hatred for them as unbelief, hypocrisy and rebellion.
Speaking well of them means mentioning them respectfully, acknowledging their religious standing and avoiding disparagement. The contrast between love and hostility conveys the gravity of one's attitude toward the Companions.