By this he meant the Spirit, whom those who believed in him were later to receive. From Pentecost to Parousia Jesus gives his mission assignment to his people. The assignment begins when thirsty sinners come and drink so the completed work of the cross becomes ours by faith. God sees us through the cross and declares us to be holy and pure, just like Jesus. Faith receives the promise and clings to the Word.
Faith drinks deep of the water of life.
The assignment continues as the Spirit is outpoured in and through us. He flows from the inner most being of the believer. Not just one stream, but many streams. Think of it. He flows from my heart, out of my very life.