فَإِنِ اقْتَصَرَ عَلَى ذِكْرِ اللَّهِ تَعَالَى: جَازَ عِنْدَ أَبِي حَنِيفَةَ رَحِمَهُ اللَّهُ، وَقَالَا: لَا بُدَّ مِنْ ذِكْرٍ طَوِيلٍ يُسَمَّى خُطْبَةً.
Translation: For Abu Hanifah, merely mentioning Allah suffices; Abu Yusuf and Muhammad require a substantial remembrance that may properly be called a sermon.
Abu Hanifah focuses on the occurrence of remembrance of Allah; Abu Yusuf and Muhammad require a discourse recognizable as a khutbah. The disagreement concerns the validity minimum, not whether a meaningful sermon is preferable.