Today, in our church calendar, we remember Pentecost- the day when the Holy Spirit came. He is the promise of the Father (Acts 1:4 ; Jn 14:16,26) and of the Son (Jn 16:7) to the church. Jesus says : “ It is to your advantage that I go away , for if I do not go away, the Helper will not come to you. But if I go, I will send Him to you.”
A few introductory remarks:
The Holy Spirit is called “ruach” in the Hebrew OT, and “pneuma hagios” in the Greek Septuagint and NT. This literally translates as “breath” (e.g. Genesis 2:7 ) or “ holy wind” Jesus, in Jn 3:1-8 likens the Spirit to the wind. With this in mind we must not be tempted to think of the Holy Spirit as an impersonal force or influence. Many in history have been tempted to think of the Holy Spirit as an ‘it’ (a thing / influence), rather than a “He” - a Person(ality). The Lord Jesus spoke about Him and when He comes in John 14 & 16  in terms of a real person, who stands apart from God the Father and God the Son, yet sharing the very attributes of God. For this reason the church in history has often referred to Him as the third member( or person) of the Godhead or the Trinity .
Like the Lord Jesus Christ (the promised Messiah), the Holy Spirit does not simply appear in the NT. They are both known and spoken of in the OT. It is true however that they are both revealed in a fuller measure in the NT. In fact, the doctrine of the Trinity has become only obvious in the light of Christ’s and the Spirit’s coming. Because of this we can also know the Father better. The Lord Jesus Christ has come to ‘exegete’ and show us the Father (Jn 1:18 ; 14:9) and the Holy Spirit (John 14- 16).
The Holy Spirit as the wind or breath, the Life Giver, is the eternal Holy Spirit (Hebr 9:14). This is one of God’s attributes. The Holy Spirit has also been there at the beginning of creation…. “and the Spirit of God was hovering over the face of the waters.” (Gen 1:2). He orders and completes and executes what has been planned in the mind of God the Father. In the NT the Holy Spirit applies the redemption wrought by Christ to our fallen natures . He helps us see the horrible nature of our sin (through conviction) and at the same time He helps us to understand the glorious work of Christ on the cross (through comforting). So we see that the Father has planned our redemption ; Jesus the Son is our redemption , and the Holy Spirit applies that redemption by helping helps dead sinners to see , believe and receive that redemption .
There is yet another work that the Holy Spirit is engaged in. Both in the OT and the NT He empowers people. However, there is a crucial difference in His work in the NT. In the OT the Holy Spirit came upon people, empowering them for various tasks for which they needed help.  In the NT, the Holy Spirit would be perpetually with and in the life of every true believer (see Jn 14:16 & 17 !). Ever since Pentecost, the Holy Spirit resides permanently among, in and with God’s people. In this He continually empowers believers in the work of witnessing to Christ’s work on the cross (Acts 1:8), and He helps them to produce fruit in keeping with repentance (Gal. 5:22,23). He also helps them in prayer and intercedes for them. (Rom 8:26-27)
All this by way of a broad introduction to the person and work of the Holy Spirit, whom we are now privileged to have in us and with us. His presence makes the living church a unique institution upon the face of the earth. No other body of people is so favoured and indwelt by God as the true church is. No other organization has as much real power and authority and the presence of God as the true church has. I say “true church”, because not every church is a true church. Many so called churches no longer walk in fellowship with the Spirit. Many have grieved the Holy Spirit. They have been abandoned by Him, as He had abandoned the temple of Israel in the days of Ezekiel (Ezekiel 10). Let us frequently learn to examine ourselves and pray like David : “Cast me (us) not from your presence , and take not your Holy Spirit from me (us) .”
Frequently Asked Questions
And now we shall look at some peculiar questions relating to the coming of the Holy Spirit in the book of Acts. It is worth our while to take some time to answer these, since the church in the 20th century has suffered severely from a lack of mature reflection upon the nature of Pentecost - the coming of the Holy Spirit . We will deal with four questions frequently asked concerning Pentecost : 
1. Were the disciples of Christ genuine believers before Pentecost? What difference did Pentecost make?
2. How is the day of Pentecost (Acts 2) related to subsequent outpourings of the Spirit in Samaria (Acts 8:4-25) , in Caesarea (Acts 10:1ff) , and Ephesus (Acts 19: 1-7) ? A related question to this is: do these passages about the outpouring of the Holy Spirit after Pentecost point us to a second experience of the Holy Spirit?
3. What is the relationship between Pentecost and the baptism of which Paul speaks in 1 Corinthians 12:13?
4. Is Pentecost a repeatable event ? Should we expect tongues and fire to descend on modern congregations ?
Since these questions cannot be dealt with in the course of the time that we have available this morning, I will only answer the first question and deal with the next three questions in our evening service.
1. Were the disciples of Christ genuine believers before Pentecost ? What difference did Pentecost make ?
The question is sometimes asked whether the disciples of Jesus were true believers before Pentecost. If the Holy Spirit is needed to help us to see our sin and our need for Christ, then it is sometimes argued that they may have become true believers only at Pentecost, for that is when the Spirit was given! To say that is to portray one’s ignorance concerning the work of the Holy Spirit in the OT. The Holy Spirit of the OT is the same Spirit of the NT. He is mentioned 88 times in the OT, although the actual term “Holy Spirit” is only mentioned 3 times in the OT (e.g. Ps 51:11) . Other terms used are e.g. “the Spirit of God” (Gen 1:2). 23 OT books refer to the Holy Spirit. The Holy Spirit certainly was known before Pentecost. He is frequently mentioned in the gospels which all refer to events before Pentecost . Jesus taught about the Holy Spirit in John Chapters 14 and 16. The Holy Spirit was certainly known and active in the OT and in the days of Christ on earth.
There can be no doubt that the disciples (minus Judas the traitor) were genuine believers before Pentecost. In John 13 Jesus makes it explicitly clear that all of the disciples were cleansed (Jn. 13:10) and united to Christ (Jn. 15:1-11) - all except Judas (cf. Jn. 13:10,11,18,21 ; Jn. 17:12). How then were OT believers justified, since neither Christ, the Messiah (who provides atonement) nor the Holy Spirit (who convicts us of our sin and opens our eyes to receive Christ) had yet been given?
The answer is deeply profound , but not difficult: All God’s people were ultimately chosen (predestined) in eternity past (see Eph 1:3-14 ; Romans 9 ; 1 Thess 1:4,5). All God’s chosen people were seen as being in Christ , before the work of the cross actually happened in the course of time. How was Abraham, for instance, redeemed from his sin and accounted righteous before God, even though He had not yet heard of or seen Christ? The answer is that it was the Holy Spirit in him that stirred his faith, and made him believe in God’s future provision of grace. He looked forward, in faith. to the fulfillment of God’s promises ? And how are you redeemed? In the same way . The Holy Spirit stirs up faith in you and you look backward to the cross of Christ and by faith in Him you are saved . The cross is found at the center of history. The OT believer looks forward to the cross, by faith, to the fulfillment of God’s promises and the NT believer looks backwards to the cross, by faith , helped by the Holy Spirit ( who shows you the Scriptures) , and so you are redeemed , justified and adopted into God’s family! Christ’s death is the ground for every believer’s justification- whether they live before the cross or after the cross . From the perspective of the Pre – Pentecost disciples of Jesus, they were saved because Jesus was going to lay down His life for them (minus Judas)
But what was the difference between their pre Pentecost and post Pentecost experience? Was there any advantage gained for them by their Pentecostal experience? Is there an improvement of the knowledge of God from the OT to the NT ? Absolutely !
B.B. Warfield writes in his book : “The Biblical Doctrine of the Trinity” :
The Old Testament may be likened to a chamber richly furnished but dimly lighted; the introduction of light brings into it nothing which was not in it before; but it brings out into clearer view much of what is in it but was only dimly or even not at all perceived before. The mystery of the Trinity is not revealed in the Old Testament; but the mystery of the Trinity underlies the Old Testament revelation, and here and there almost comes into view. Thus the Old Testament revelation of God is not corrected by the fuller revelation which follows it, but only perfected, extended and enlarged.
At Pentecost a phenomenal leap took place. The disciples gained a confidence, knowledge, power and a equipping for the task of making the ancient plan of God, the gospel, (embodied in His Son, the Lord Jesus) effectively known to the entire world. Because of Pentecost they and we were enabled to effectively carry out the Great Commission (Matt 28:18-20) to the nations. You and I have not only become recipients of that gospel, but we been also empowered to share that Gospel today. Thank God for Pentecost !
 See especially John 16:12-15
 E.g. Bezalel & Oholiab (Ex 31:1ff); Judges 3:10 ( Ehud) ; 6:34 ( Gideon); 14:6,19; 15:14 ( Samson); 1 Samuel 10:10; 11:6 (Saul) ; Ezekiel 2:2; 3:12,14 etc ( Ezekiel)
 One of his names is the ‘ paraclete’ lit. one who comes alongside , hence ‘ with’
 Taken from Sinclair Ferguson : The Holy Spirit : Ch 4- Pentecost Today? P. 79
 Luke speaks about the Holy Spirit in the gospel a number of times, particularly in the life of John the Baptist and Jesus. Jesus teaches His disciples also to expect the Holy Spirit to help them prior to Pentecost (see for example Lk 11:13; 12:12 ; and again in John 14 & 16)