The Apostle declares, "He that is joined unto the Lord is one spirit" (1 Cor. 6:17). If, then, we are joined to the Lord, in other words, have a union with him, this is the closest of all unions.
A man and his wife are one flesh, but Jesus and the saint are one spirit. If possessed of this we are one spirit with him; we understand what he says; we have the mind of Christ; we love what he loves, and hate what he hates.
But out of this spiritual union flows communion with him, intercourse with him, communications from him, and the whole of that divine work upon the heart whereby the two spirits become one. The Spirit of Christ in his glorious Person and the Spirit of Christ in a believing heart meet together, and meeting together as two drops of rain running down a pane of glass, or two drops of oil, kiss into each other, and are no longer two but one.
Now if you have been ever blest with a manifestation of Christ, your spirit has melted into his, and you have felt that sweet union and communion with him that you saw as with his eyes, heard as with his ears, felt as with his heart, and spoke as with his tongue.