One must be logical and be able to quote from the scriptures to backup arguments and not blindly accept anything nor be falsely hyped up, and be tolerant and merciful to everyone. Such persons have highly elevated consciousness and are the topmost devotees.

“One who is expert in logic, argument and the revealed scriptures and who has firm faith in Kṛṣṇa is classified as a topmost devotee. He can deliver the whole world. ‘One who is expert in logic and in understanding the revealed scriptures, and who always has firm conviction and deep faith that is not blind, is to be considered a topmost devotee in devotional service.” (Śrī Caitanya-caritāmṛta Madhya 22.65-66)
“Devotees are always tolerant, forbearing and very merciful. They are the well-wishers of every living entity. They follow the scriptural injunctions, and because they have no enemies, they are very peaceful. These are the decorations of devotees.” (Śrī Caitanya-caritāmṛta Madhya 22.81)