The spirit of bondage works by fear for the slave fears the rod: but love cries, Abba, Father; it disposes us to go to God, and behave ourselves towards God as children; and it gives us clear evidence of our union to God as His children, and so casts out fear. So that it appears that the witness of the Spirit the apostle speaks of, is far from being any whisper, or immediate suggestion or revelation; but that gracious holy effect of the Spirit of God in the hearts of the saints, the disposition and temper of children, appearing in sweet childlike love to God, which casts out fear or a spirit of a slave.
Jonathan Edwards, The Religious Affections