Wesley's signature doctrine of assurance — that the Holy Spirit directly witnesses to the believer's spirit, giving inward certainty of God's love.
Sermon 10 of 44 · 1746 · Romans 8:16
The Witness of the Spirit, I
A passage from the sermon
The testimony of the Spirit is an inward impression on the soul, whereby the Spirit of God directly witnesses to my spirit that I am a child of God; that Jesus Christ hath loved me, and given himself for me; that all my sins are blotted out, and I, even I, am reconciled to God.
This testimony is what the apostle calls 'the spirit of adoption, whereby we cry, Abba, Father.' It is by the witness of the Spirit that we are enabled with full assurance to address God as our Father, and to know that we are His children. Without this witness, however much faith we may profess, we are still in the spirit of bondage; with it, we have entered into the liberty of the children of God.
The full sermon is in the public domain and freely available from CCEL and other archives.