Indwelling of the Spirit
The statements ‘Spirit of God lives in you’, ‘have the Spirit of Christ’ and ‘Christ is in you’ are three ways of describing the single reality of the indwelling of the Spirit. This complex, multi-layered phenomenon indicates that there is an economic identity between Christ and the Spirit.
Sinclair Ferguson, The Holy Spirit, ed. Gerald Bray, Contours of Christian Theology (Downers Grove, IL: InterVarsity Press, 1996), 37.