That is a good question. My initial thought is that passages like Ezekiel 18 and Romans 2:6 are clear that God judges (i.e. holds us guilty) on an individual basis, but it is also possible and right that we should identify with and intercede for our fellow sinner (along with ourselves). Daniel does this, as you mention, and I would argue that is one reason why the Lord's Prayer teaches us to pray "forgive us" in the plural (not just "forgive me"); identifying with sinners and pleading for their forgiveness is one of the most Christ-like things we can do, as Christ identified himself with sinners in accepting a baptism "for repentance" and in his great prayer from the cross "Father, forgive..." As always, what the Father does with that prayer is up to Him.
What does your theory say about Daniel who when he prayed for his countrymen for their sins, included his own sins in his prayer?
That is a good question. My initial thought is that passages like Ezekiel 18 and Romans 2:6 are clear that God judges (i.e. holds us guilty) on an individual basis, but it is also possible and right that we should identify with and intercede for our fellow sinner (along with ourselves). Daniel does this, as you mention, and I would argue that is one reason why the Lord's Prayer teaches us to pray "forgive us" in the plural (not just "forgive me"); identifying with sinners and pleading for their forgiveness is one of the most Christ-like things we can do, as Christ identified himself with sinners in accepting a baptism "for repentance" and in his great prayer from the cross "Father, forgive..." As always, what the Father does with that prayer is up to Him.