Shaykh Muqbil bin Haadee (rahimahullaah) stated about Shaykh Rabee bin Haadee:
وأنا أنصح الأخوة بالاستفادة من كتب أخينا الشيخ ربيع بن هادي - حفظه الله تعالى - فهو إن شاء الله [بصير] بالحزبيين، ويخرج الحزبية بالمناقيش، قال بعضهم: إنّ بعض المحشين على الكشاف يخرج الاعتزال بالمناقيش، هذا - أيضاً - يخرج الحزبية بالمناقيش، أنا أنصح بالاستفادة من كتبه، وكذلك بالاستفادة من أشرطته
And I advise the brothers to benefit from the books of our brother Shaykh Rabee bin Haadee - may Allaah protect him - for he is, if Allaah wills, insightful with respect to the Hizbiyyeen and he brings out this Hizbiyyah (present with people) with chisels, one of them said, "One of the commentators upon al-Kashshaaf brings out al-I'tizaal through chisels" and this one also (Shaykh Rabee), he brings out Hizbiyyah through chisels. I advise with benefiting from his books and likewise benefiting from his cassettes.
Source: In the cassette (الأسئلة السنية لعلاّمة الديار اليمنية، أسئلة شباب الطائف) and as published in (الثناء البديع من العلماء على الشيخ ربيع) by Shaykh Khalid al-Dhufayree. The book al-Kashshaaf is one of the tafseer books of the Mu'tazilah written by al-Zamakhsharee, who put in a lot of I'tizaal (madhhab of the Mu'tazilah) but in ways that are very subtle, involving the subtleties of language. And Shaykh Muqbil is indicating how one of the commentators (who wrote footnotes to it) was able to 'chisel out' all of the i'tizaal (due to his insight). In the same way, he described Shaykh Rabee, whose insight into the jamaa'aat and hizbiyyeen, allows him to 'chisel out' hizbiyyah.