Chastisement: correction, punishment, rebuke, reprimand, admonish, reprove, lecture, lambaste or berate.
Hebrews 12:6-11 For whom the Lord loves He chastens, and scourges every son whom He receives.” If you endure chastening, God deals with you as with sons; for what son is there whom a father does not chasten? But if you are without chastening, of which all have become partakers, then you are illegitimate and not sons. Furthermore, we have had human fathers who corrected us, and we paid them respect. Shall we not much more readily be in subjection to the Father of spirits and live? For they indeed for a few days chastened us as seemed best to them, but He for our profit, that we may be partakers of His holiness. Now no chastening seems to be joyful for the present, but painful; nevertheless, afterward it yields the peaceable fruit of righteousness to those who have been trained by it.
The chastisement of the Lord is meant to produce holiness. In other words, the person was living an unholy life, so the Lord spanked him. That spanking was meant to change the person's behavior, it's up to the person to respond to the spanking in a positive way, through repentance. If the person is not trained by the spanking, but rather, they harden their heart, and continue living the unholy life style, they will not see the Lord, nor will they have a share in all that belongs to Yeshua.
Hebrews 12:14 Work at living in peace with everyone, and work at living a holy life, for those who are not holy will not see the Lord.
Hebrews 3:12-14 Be careful then, dear brothers and sisters. Make sure that your own hearts are not evil and unbelieving, turning you away from the living God. You must warn each other every day, while it is still “today,” so that none of you will be deceived by sin and hardened against God. For if we are faithful to the end, trusting God just as firmly as when we first believed, we will share in all that belongs to Christ.
We must be worthy to take part in the first resurrection, and be part of the age to come.
Luke 20:35 But those who are considered worthy of taking part in the age to come and in the resurrection from the dead will neither marry nor be given in marriage.
1 Thessalonians 2:11-12 For you know that we dealt with each of you as a father deals with his own children, encouraging, comforting and urging you to live lives worthy of God, who calls you into his kingdom and glory.
To walk worthy is to live holy i.e. live a set apart life for God..
Romans 6:22 But now you are free from the power of sin and have become slaves of God. Now you do those things that lead to holiness and result in eternal life.