Hi Bernard.
Paul seem to be involved in a discussion.
In verses 1-4 he accepts that " the Jews* were entrusted with the oracles of God.". Next Paul asks, "3What if some were unfaithful? Will their faithlessness nullify the faithfulness of God?". Paul answer this question like this: "4By no means! Although everyone is a liar, let God be proved true, as it is written,
‘So that you may be justified in your words,
and prevail in your judging.’* "
Psalm 116.
8 For you have delivered my soul from death,
my eyes from tears,
my feet from stumbling.
9 I walk before the LORD
in the land of the living.
10 I kept my faith, even when I said,
‘I am greatly afflicted’;
11 I said in my consternation,
‘Everyone is a liar.’
Psalm 51
Psalm 51
To the leader. A Psalm of David, when the prophet Nathan came to him, after he had gone in to Bathsheba.
1 Have mercy on me, O God,
according to your steadfast love;
according to your abundant mercy
blot out my transgressions.
2 Wash me thoroughly from my iniquity,
and cleanse me from my sin.
3 For I know my transgressions,
and my sin is ever before me.
4 Against you, you alone, have I sinned,
and done what is evil in your sight,
so that you are justified in your sentence
and blameless when you pass judgement.
5 Indeed, I was born guilty,
a sinner when my mother conceived me.
6 You desire truth in the inward being;*
therefore teach me wisdom in my secret heart.
5But if our injustice serves to confirm the justice of God, what should we say? That God is unjust to inflict wrath on us?
6By no means! For then how could God judge the world?
In verses 6 and 7 we are told that the justice of God judges us guilty; we deserve " the wrath of God".
7But if through my falsehood God’s truthfulness abounds to his glory, why am I still being condemned as a sinner? 8And why not say (as some people slander us by saying that we say), ‘Let us do evil so that good may come’? Their condemnation is deserved!
Justice and mercy is what Paul seems to be examining as it applies to humanity. as this comment of Rashi to Gen 1.1 explains:
God’s creation of the heavens and the earth: But it does not say “of the Lord’s creation of” (i.e., it should say “of the Lord God’s creation of” as below 2:4 “on the day that the Lord God made earth and heaven”) for in the beginning it was His intention to create it with the Divine Standard of Justice, but he perceived that the world would not endure; so He preceded it with the Divine Standard of Mercy, allying it with the Divine Standard of Justice, and that is the reason it is written:“on the day the Lord God made earth and heaven.”
http://www.chabad.org/library/bible_cdo ... rashi=true