Make yourself tender to the voice of the Lord - His Word and His HolySpirit.

When a person hardens their heart toward the Lord it is an overt act of rebellion. It results in an impenetrable eternal spiritual state from which there is no hope of salvation.
This is not to be confused with running from the Lord which many have done and do today.

No one comes to the Lord purely on their own. They are drawn by the HolySpirit as they hear the Gospel. Those who believe and receive the Gospel are saved. Those who reject the Gospel have spurned the HolySpirit and so may never be bothered by Him again.