An emphasis on the importance of prayer and purification for the task of theologizing can be found in some quarters at the moment, and I have touched on the topic previously myself in respect to Gregory of Nazianzus.
At the same time, we should remember that there is nothing peculiarly “patristic” about this emphasis, and that it did not lie dormant in those long centuries between late antiquity and now. One can find it frequently in the Reformers, and I include here a succinct statement of the idea from Philipp Melanchthon, from the same oration “On the Difference between the Church of God and Worldly Sovereignty” from which I quoted a couple of days ago. Melanchthon draws attention to the importance of study and piety for the teacher; for the only effective teacher will be one who orders his life in accordance with the “standard” (normam) of the Gospel.
Custodiri autem pura doctrinae sententia sine lectione, meditatione et collatione eruditorum non potest, imo ad hoc studium etiam precatio pia addenda est, ut Deus mentes et iudicia regat, sicut saepe dicitur in Psalmo: Iustificationes tuas doce me. Addi etiam oportet exercitia pietatis in moribus, quae sunt lumen doctrinae. Nam ita demum alios recte docebimus, cum prius nos ipsos erudiemus, et ad Evangelii normam dirigemus nostram conscientiam et vitam.
Pure opinion in doctrine, moreover, cannot be guarded without reading, meditation, and comparison of educated [writers]; nay,there must also be added to this study the pious prayer that God would guide our minds and judgments, as it is often said in the Psalm: “Teach me your justifications.” It is also proper that there be added the exercises of piety in morals, which1 are the light of doctrine. For only then will we rightly teach others, when we educate ourselves and direct our conscience and life according to the norm of the Gospel.2