External appearances are all that we can see.  Religion, wherever it may be found, tends to accumulate external symbols, rites and ceremonies which are considered 'essential' for anyone who wants to be a part of it.  That was the Jewish background too.  When some Jews believed in Jesus as the Messiah, they wrongly thought the signs guaranteed their salvation.

These seem technical, almost legal, arguments.  But they reveal God’s character and refute false human ideas about Him.  The key question in these verses is ‘Is God fair to condemn sinners who cannot help sinning?’  Parallel questions are, ‘Does God need our badness for Himself to be seen as infinitely good by comparison?’, and ‘Does He need our unrighteousness to demonstrate His own glory?’  In other words, is God’s glory like that of conquering imperial warlords whose glorious power is demonstrated in the brutal treatment of the conquered?  

Most of the time, people act in a socially acceptable way.  They are restrained from breaking laws because they fear punishment, and controlled by social traditions because they fear being excluded.  However, underneath the external niceness lie hearts which can produce poisonous speech and violent actions. That is why drunkenness is so ugly; it is not 'the alcohol talking', but the real man or woman is being displayed as inhibitions are removed. These verses quoted from the Psalms reveal that nobody's nature is good enough for God.

The Apostle Paul has been relentless in describing God’s judgement of sin from Romans 1:18-3:20.  Much of the writing was addressed to the Jewish-background believers who were basing their spiritual confidence in their knowledge of God’s Law with its heritage and rituals.  But none of that could save them or make them righteous before God.