And Luke 13 describes the properly diligent seeking as an agonizing thing. Jeremiah reveals that nothing else even counts as seeking. We must have a hungering and thirsting after righteousness (Matthew's Beatitudes).
So, the seeking is very serious.
But Paul drops a logical bombshell when he says that NO ONE SEEKS THE LORD.
And the only solution is the Calvinistic one. It is the same thing as the Lord was saying in John 6:44.