The parable of the tares represents the final judgment. God leaves all mankind and even his church for Judgment Day. This does not diminish the need for discipline within the church. In fact, it becomes a greater need, if possible. Whoever uses this parable to justify inaction is either woefully naive or maliciously sowing more tares.
Loss means change means pain means discipline of the Lord toward holiness.
Self-discipline is, in large part, the capacity to say no, both to the bad and to the good, in order to dedicate oneself to the best.
God’s holy remnant in Israel were the victors of his discipline. Today his church submits itself to that same discipline. “But on Mount Zion there will be a remnant which will be holy” Ob 17 REB.