The more we understand the reason underlying man's sinful condition, the more we can appreciate the wisdom and beauty of the genuine saving grace of God.
Take John the Baptist for example, he was the forerunner going forth to minister in the spirit and power of Elijah - listen to the words of the angel - his words reveal the heart condition that John would be seeking to turn the people from and the right heart John would be seeking to turn them towards.
"....to turn the hearts of fathers upon children and those who REFUSE TO BE PERSUADED to the PRUDENT MIND of the righteous."
The reason Israel was in their depraved spiritual condition was their persistent refusal to be persuaded by God's many attempts to correct them. The sickness of their heart was persistent resistance to persuasion - this was the testimony of all the prophets, summed up in this statement - "all day long I have held out my hands to a people who refuse to be persuaded and who speak contrary."
This is what John's ministry must address! He was sent to turn the people from their persistent resistance to the word of the Lord, towards "the prudent mind of the righteous." What then is "the prudent mind of the righteous"? Simply put, it is the frame of mind formed by HEARING, RETAINING, and UNDERSTANDING the word of the Lord.
"The righteous one lives by faith" and "faith comes from HEARING" the word of the Lord. Israel's spiritual condition was caused by persistent refusal to hear the word of the Lord and John was filled with the Spirit to call them to repentance from this stubbornness of heart.
This is the work that the true grace that brings salvation does! It teaches, trains, disciplines us to deny the ungodly stubbornness of persistent resistance to hearing the word of the Lord and to reject the carnal propensity to live according to our own base desires so as to live soberly, righteously, and godly in this present world.
The ministry of repentance is still needed wherever man's persistent refusal to be persuaded still has them living in the darkness of their own understanding.
The ministry of the Holy Spirit must convict the world of SIN - the unbelief that results from persistently refusing to hear, retain, understand, and do the word of the Lord.
May THIS grace be multiplies unto you from God the Father and Christ Jesus our Lord!