Messenger of Allah, no person is more excellent than he after Messenger of Allah ﷺ. Thereupon Allah's Apostle ﷺ said: Woe be to thee, you have broken the neck of your friend, and he said this twice. Then Messenger of Allah ﷺ said: If anyone has to praise his brother at all, he should say: I think him to be so and so, and even on this he should say: I do not consider anyone purer than Allah (considers). (Using translation from Muslim 3000b)
عَنِ النَّبِيِّ ﷺ أَنَّهُمْ ذَكَرُوا رَجُلًا عِنْدَهُ فَقَالَ رَجُلٌ يَا رَسُولَ اللهِ مَا مِنْ رَجُلٍ بَعْدَ رَسُولِ اللهِ ﷺ أَفْضَلُ مِنْهُ فِي كَذَا وَكَذَا فَقَالَ النَّبِيُّ ﷺ وَيْحَكَ قَطَعْتَ عُنُقَ صَاحِبِكَ مِرَارًا يَقُولُ ذَلِكَ قَالَ رَسُولُ اللهِ ﷺ إِنْ كَانَ أَحَدُكُمْ مَادِحًا أَخَاهُ لَا مَحَالَةَ فَلْيَقُلْ أَحْسَبُ فُلَانًا إِنْ كَانَ يَرَى أَنَّهُ كَذَاكَ وَلَا أُزَكِّي عَلَى اللهِ أَحَدًا وَحَسِيبُهُ اللهُ أَحْسَبُهُ كَذَا وَكَذَا