Al-Qushayri, the Sufi scholar, writes that the fear of God (تقوى) has three aspects: “… full trust in God with respect to what has not been granted to him; full satisfaction with what has been granted to him; and full patience with respect to what has eluded him.”
In terms of the lover and the Beloved, consider how a lover’s heart would be affected if he were offered a hundred mithqals of gold to betray his beloved. That reaction, if true to his love, is تقوى. I believe this state of being is also echoed in the following passage of the Kitáb-i-Aqdas:
Whoso hath inhaled the sweet fragrance of the All-Merciful, and recognized the Source of this utterance, will welcome with his own eyes the shafts of the enemy, that he may establish the truth of the laws of God amongst men.
In this state of being, one’s chastity of soul (that is, singleness of desire for God) becomes so refined that even a single misstep from the Straight Faith would be reckoned as though stepping into white hot fire.
Outwardly it is seen as fear, inwardly it is a condition of being. The تقوى of the body prevents one from holding their breath too long; the تقوى of the نفس is clinging to the Law and the Path with every fiber of one’s being; and the تقوى of the spirit (روح) is the continual testimony: “… all exemplify the truth that there is none other God but Him”.
Even between the lover and his beloved: Something causes him to take care that his words and actions always express his heart; he never acts carelessly toward his loved one.