"God looks down from heaven
on the children of man
to see if there are any who understand,
who seek after God.
They have all fallen away;
together they have become corrupt;
there is none who does good,
not even one." - Psalm 53:2,3
The idea that all of mankind is totally depraved as part of our nature is a clearly biblical doctrine
Through passages such as these and the ones found in the book of Romans (1-3, 6 and 7), we can construct a clear idea from Scripture that man is in a very bad state indeed, unable to even help themselves in their fight to know God and experience His love and forgiveness.
Our deeds are as filthy rags before Him (Isaiah 64:6), whose standard is PERFECTION.
We have all sinned and fallen short of the glory of God (Romans 3:23), and the Bible even goes as far as to say that we are all DEAD in our trespasses (Ephesians 2:1).
BUT (I love that word when it is used in the Bible!), GOD, "being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ - by grace you have been saved." (Ephesians 2:4)
"We are more wicked than we ever dared believe, but more loved and accepted in Christ than we ever dared hope — at the very same time. This creates a radical new dynamic for personal growth. It means that the more you see your own flaws and sins, the more precious, electrifying, and amazing God’s grace appears to you." - Timothy Keller