In John 16:7-8 Jesus talks about the two mains jobs of the Holy Spirit:
[Jesus said] “Nevertheless, I tell you the truth: 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.  And when he comes, he will convict the world concerning sin and righteousness and judgment.”
First, the Holy Spirit is our helper. The actual word is paraclete. It means to be called to one’s side. The Holy Spirit is called to our side to help us.
It is very common to call people to be by one’s side. If one is sick, if one is dying, if one is facing any kind of difficult situation, it is common to call a trusted person to be by their side.
It is so hard to go through difficult times all alone. Yet when we have someone by our side we can handle things much better. Thankfully, now that concerns about the COVID-19 pandemic are easing, more hospitals and nursing homes are allowing loved ones to be by the side of family members who are suffering.
Earlier, in John 15:26, Jesus had told the disciples what the Holy Spirit would do when he is by our side: “But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, he will bear witness about me.”
The other work of the Holy Spirit is to convict the world of sin, righteousness and judgment. He convicts us of our sins in such a way that we despair of our own righteousness and feel the judgment of God upon us. The reason the Holy Spirit does this is so that he can then help and comfort people. The Holy Spirit does one of his jobs in order to get to the other job.
In our Lutheran confessions it states: “Therefore the Spirit of Christ must not only comfort but through the function of the law must also “convict the world of sin.”
On the Day of Pentecost the Holy Spirit worked in both ways. In Acts 2 we are told that when Peter was done preaching on the Day of Pentecost the people were convicted of their sin and then told about the Holy Spirit’s comfort:
“Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, ‘Brothers, what shall we do?’  And Peter said to them, ‘Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.  For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.’” (Acts 2:37-39)
The Holy Spirit comforted people with the good news of forgiveness of sins through faith in Jesus Christ and he also cut people to the heart.
When it comes to convicting people of sin the Holy Spirit is not going to stop there. Once he has convicted us of our sins he immediately brings comfort to us by pointing us to Jesus.
The way that the Holy Spirit does this is through his ministers. As soon as the Holy Spirit was poured out on the Apostles on the Day of Pentecost, Peter stood up with the other eleven disciples and began explaining what was going on.
Jesus told his disciples in John 20, “As the Father has sent me, I am sending you.” Why would Jesus take time to tell his disciples all about the work of the Holy Spirit if they were not to be involved in it, if the Holy Spirit was just going to do his work directly as he did on the Day of Pentecost?
The Holy Spirit still comforts us and still convicts the world of sin. It’s just that now he does so through the ministry of the Word.
Again, why would Jesus institute the sacraments of Holy Baptism and the Lord’s Supper and command us to use them if not so that his ministers could be the ones through whom the Holy Spirit works?
God sends out his ministers to do the work of the Holy Spirit. They convict people of their sins and then come alongside them to comfort them with the good news.
The Holy Spirit has a two-part job. He convicts people of sin. Then he comes alongside them and helps and comforts them with the Gospel: The promise of forgiveness, life and salvation is for you and for your children, everyone whom the Lord our God calls to himself.