Note that the Lord said His Spirit was striving with man. The Hebrew word for striving is a primary root and denotes principally to rule or to judge but the sense we have here is of contending with man - pleading a cause.There came a point when His longsuffering ended. However, I don’t think it was a matter of God getting tired of presenting the truth or convicting their hearts, because he doesn’t tire and never changes in character. Rather, there came a point when man’s heart got so used to sin and so hard that it could no longer receive truth, it simply wasn’t possible for it to hear truth or receive conviction.