“Those newly embarked on the ascetic life are assisted in the practice of the commandments and in their escape from evil by fear of punishment. But in those who through virtue have advanced to the contemplation of God’s glory this fear is followed by another fear – a pure fear (cf. Ps. 19:9) – which, because it is caused by love, fills them with great dread. This helps them to stand unshaken in their love for God, instilling in them terror at falling away from such love.”
(Nikitas Stithatos in ‘The Philokalia’)