Doubts about the function of the holy communion

I have been attending a Lutheran spirituality course at my church led by my pastor. The material used for the course is a book titled “The spirituality of the cross – The way of the first evangelicals (Revised Edition)” by Gene Edward Veith, Jr.

The course so far emphasizes the viewpoint that grace and salvation comes from God, rather than it being the merit of good works by human individuals. Even the ability to have faith is deemed to be the work of God, as sinful human beings are unable to believe on their own accord. As such, no one should claim himself superior to his fellow human being, but should be humble and grateful for his belief and salvation.

The other point that is tied in is that of the sacraments. The sacraments seem to be a key feature in Lutheran spirituality on how God administrate his gifts and saving grace to believers. So rites like baptism of infants, and the partaking of the holy communion, are deemed to be essential practice for the salvation and forgiveness of sins.

I have some reservations though about this idea of sacraments, especially the part about the partaking of holy communion as being essential for the forgiveness of sins. For one, I don’t like the idea of the institutional church claiming for itself the key to forgiving people’s sins. I just have an aversion towards the idea that there needs to be another layer of ritual for the forgiveness of sins apart from the simple prayer for God to forgive one’s sins, and that the means of the latter is inferior to the former. The key bible passage for examination regarding the function of holy communion seems to be Matthew 26:27, where Jesus took the cup of wine, and told the disciples to drink from it, saying “This is my blood of the covenant, which is poured out for many for the forgiveness of sins”

I suppose this saying by Jesus is open to interpretations. On the one hand, it could mean the partaking of the holy communion, which is representative of the blood of Jesus, is essential to receive the forgiveness of sins. On the other hand, Jesus could be referring to his crucifixion as the blood covenant that is poured out for the forgiveness of sins. The wine in the holy communion is simply symbolic and representative of the crucifixion, and Jesus intends it to be simply a reminder rather than having the function for forgiving sins.

I favour the latter interpretation. I just don’t see why it is that God would need the practice of another ritual to administer the forgiveness of sins. The death of Jesus on the cross seems adequate to me, and salvation stemming from this is freely administered upon petition via prayers.