We know the Old Testament pattern of appointed priests (from the tribe of Levi) who served at the Temple, the focal point of God's presence, on behalf the Israelites. The whole people were in covenant before God, and within that the priests had a special role.
What is typically less understood is that the whole nation in covenant with God collectively had a priestly role for the whole world. Exodus 19:6 spells this out - a calling on the whole people to somehow serve before God on behalf of the world
As Christians we should know that Jesus made it clear that access to God is direct for any who would turn, without needing any human mediation. With Jesus there is no need for any kind of special or professional minister to mediate on our behalf - simply turn to Jesus.
Yet there is still a sense that those who do turn to follow Jesus then find themselves in a priestly role for the rest of the world. Peter describes a priesthood of all believers (1 Peter 2:9), fulfilling that Exodus promise. Paul also describes a priestly role in Romans 15:16. Somehow we are called to mediate God's presence to others, who would otherwise remain far from God in their everyday lives.
5 years ago my colleagues staged a celebration banquet. It was the Queen's jubilee year, and so we decided to throw a meal for people on the margins in the city. We cooked, we laid out tables with union jacks, and we sent word out for people to come.
Only about 10 came, but we ate together and had fun - singing favourites like 'Land of Hope and Glory'.
For me that started a ministry-friendship with a guy who was in and out of struggling with alcohol addiction. He had bounced in and out of churches, he sofa-surfed, and generally struggled along. Myself and others talked and prayed with him through his many ups and downs. In recent years his spiritual life had some positive developments, although he still cycled in and out of addiction.
Sadly this year his health failed, and he passed away. It was then that we discovered just how many people across the city both knew and loved this one man. The funeral was held elsewhere by his family, but it quickly became obvious that we needed to offer a focus for grieving and remembering locally - so we organised this at the church building.
Some 75 came - from very diverse walks of life. Some were in addiction recovery, others still in the grip of addictions of unhealthy life patterns ... but nevertheless they came for sharing and spiritual moments. Myself and my fellow Jesus-followers had a priestly role that day, welcoming and enabling a focal point of God's presence for people who would otherwise likely be far from this benefit.
We will likely never know what the long term outcome might be for any of the friends who came - but we continue in the priestly role given to us.