Questions on sentences in article

Hi,

I gotthe following sentences from the ChristianToday magazne, a magazine of evangelical conviction, by N.T. Wright on March 25, 2008, and hope you would answer some questions on them.

When we talk with biblical precision about the resurrection, we discover an excellent foundation for lively and creative Christian work in the present world--not, as some suppose, for an escapist or quietist piety.

Here, the word 'piety' seems to be uncountable, yet seems that the article 'an' is for that. Why? This is a general question but "Can a person use an indefinite article like 'a' when he thinks an instance of something or a type of something in his mind?

No single individual can attempt more than a fraction of this mission. That's why mission is the work of the whole church, the whole time. Paul's advice to the Philippians even though he and they knew they were suffering for their faith and might be tempted to retreat from the world into a dualistic, sectarian mentalitywas upbeat.

Here, I think it is right to say that in 'might be tempted', the 'might' is used to convey the sense of the past, putting his indecisive intention in the past-time setting; but I think it is safe to say that the word 'might' can be used the same or similarly in the present-time setting. But here, I think it is used in the in the past-time setting. I think you can see a similar use with the modal verb 'would'.

It is the anticipation of the time when God will fill the earth with his glory, transform the old heavens and earth into the new, and raise his children from the dead to populate and rule over the redeemed world he has made.

Here, I think 'he has made' is used because eventhough the reference is to what was made a very, very long time ago, the happening carries  a current relevance to what the writer is tryng to say and that is why the present perfect was used. Right? Why do I see 'heavens' in plural,  not 'heaven' in singular?                  

This is another question: Can you use a present perfect to refer to a historical figure who happened to live  very, very long ago or his legacy? 

Sorry for many questions

I don't know what happened but I think I typed right but came out right this: 

No single individual can attempt more than a fraction of this mission. That's why mission is the work of the whole church, the whole time. Paul's advice to the Philippians even though he and they knew they were suffering for their faith and might be tempted to retreat from the world into a dualistic, sectarian mentalitywas upbeat

It should have been this:

No single individual can attempt more than a fraction of this mission. That's why mission is the work of the whole church, the whole time. Paul's advice to the Philippians even though he and they knew they were suffering for their faith and might be tempted to retreat from the world into a dualistic, sectarian mentalitywas upbeat.

I don't know but I am typing the crossed-out part as a part enclosed with a pair of dashes but it comes out crossed out. I think quoting correctly is important, eventhough this is a general esl grammar forum, and I don't want to be blamed for misquoting what Mr. N.T. Wright's wrote.

The crossed-out part should have been this with a pair of dashes around the clause that started with 'eventhough' and ended with 'mentality':

eventhough he and they knew they were suffering for their faith and might be tempted to retreat from the world into a dualistic, sectarian mentiality

When we talk with biblical precision about the resurrection, we discover an excellent foundation for lively and creative Christian work in the present world--not, as some suppose, for an escapist or quietist piety.

Here, the word 'piety' seems to be uncountable, yet seems that the article 'an' is for that. Why? This is a general question but "Can a person use an indefinite article like 'a' when he thinks an instance of something or a type of something in his mind? I think it should be "or for quietist piety.'

 No single individual can attempt more than a fraction of this mission. That's why mission is the work of the whole church, the whole time. Paul's advice to the Philippians even though he and they knew they were suffering for their faith and might be tempted to retreat from the world into a dualistic, sectarian mentalitywas upbeat. Might just means "there was the possibility for them to be tempted"

Here, I think it is right to say that in 'might be tempted', the 'might' is used to convey the sense of the past, putting his indecisive intention in the past-time setting; but I think it is safe to say that the word 'might' can be used the same or similarly in the present-time setting. But here, I think it is used in the in the past-time setting. I think you can see a similar use with the modal verb 'would'.

It is the anticipation of the time when God will fill the earth with his glory, transform the old heavens and earth into the new, and raise his children from the dead to populate and rule over the redeemed world he has made.

Here, I think 'he has made' is used because eventhough the reference is to what was made a very, very long time ago, the happening carries  a current relevance to what the writer is tryng to say and that is why the present perfect was used. Right? Why do I see 'heavens' in plural,  not 'heaven' in singular?   The redeemed world he has made - yes it denote present perfect.                

This is another question: Can you use a present perfect to refer to a historical figure who happened to live  very, very long ago or his legacy?

 Yes, if your believe that historical figure is God who lived, is living and will live forever.