"Howbeit, when he, the Spirit of truth, is come, he will guide you into all the truth, for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. HE SHALL GLORIFY ME: for he shall receive of mine, and shall shew it unto you" John 16:13-14

Wasn’t the Spirit of God already in the world before Christ died on the cross? Most definitely yes! We see Him first mentioned in Genesis 1:2 in the creation of the world, ‘moving upon the waters.’ He was the Spirit of Faith then as now. Apart from the Spirit of God regenerating sinners in the Old Testament, none could have believed on the Christ Who was to come, being otherwise dead in their sins. It was not just that the Spirit came upon them, but Peter affirmed that ‘the very Spirit of Christ was IN them,’ 1 Peter 1:11. It was the very same Spirit of Christ, which regenerates, illumines, and draws sinners to Him today, that was at work in them, ‘testifying BEFOREHAND the sufferings of Christ, and the glory that should FOLLOW.’

So when our LORD said, ‘when He, the Spirit of Truth IS COME,’ He was clearly speaking of the presence of the Spirit in the world as an ADVOCATE, v. 7 (‘Comforter’) attesting to the work that Christ came and accomplished by His death, to satisfy God’s law and justice on behalf of sinner’s whom He had eternally chosen by His electing grace in Christ, Eph. 1:4-14. Christ is not referring here to His work of regeneration as being new, but the Spirit’s very presence in the world attesting and confirming (which an advocate does) that indeed, what God the Father purposed from eternity, Christ has accomplished in putting away the sin of His people, and the Father justifying them in one simultaneous act by His death on the cross. What the Spirit had regenerated in those of the Old Testament to know and believe through the PROMISE (Galatians 3:18), His presence now testifies as FULFILLED- FINISHED- ONCE FOR ALL.