Catechesis: Lord’s Prayer, Amen

But all depends upon this, that we learn also say “Amen.” This means that we do not doubt that our prayer is surely heard and that what we pray for shall be done. LC III:119

Therefore, where there is no such faith, there cannot be true prayer either. LC III:120

The reason for this is, they do not respect God’s promise but rely on their own work and worthiness, by which they despise God and accuse Him of lying. LC III:233