And have you [completely] forgotten the divine word of appeal and encouragement in which you are reasoned with and addressed as sons? My son, do not think lightly or scorn to submit to the correction and discipline of the Lord, nor lose courage and give up and faint when you are reproved or corrected by Him; 6 For the Lord corrects and disciplines everyone whom He loves, and He punishes, even scourges, every son whom He accepts and welcomes to His heart and cherishes. 7 You must submit to and endure [correction] for discipline; God is dealing with you as with sons. For what son is there whom his father does not [thus] train and correct and discipline? 8 Now if you are exempt from correction and left without discipline in which all [of God’s children] share, then you are illegitimate offspring and not true sons [at all]. 9 Moreover, we have had earthly fathers who disciplined us and we yielded [to them] and respected [them for training us]. Shall we not much more cheerfully submit to the Father of spirits and so [truly] live? 10 For [our earthly fathers] disciplined us for only a short period of time and chastised us as seemed proper and good to them; but He disciplines us for our certain good, that we may become sharers in His own holiness. 11 For the time being no discipline brings joy, but seems grievous and painful; but afterwards it yields a peaceable fruit of righteousness to those who have been trained by it [a harvest of fruit which consists in righteousness–in conformity to God’s will in purpose, thought, and action, resulting in right living and right standing with God].  Hebrews 12:5-11 AMP

Verse 11 says that God’s discipline yields a peaceable fruit of righteousness to those who have been trained by it.
Discipline:

The word “discipline” means instruct, train, correct. God’s discipline is administered to us by His Word and His Spirit. God does not force it on us – we must submit to it (verse 9). The fruit produced in us is fed and watered by God’s Word and His Holy Spirit.

Every Scripture is God-breathed (given by His inspiration) and profitable for instruction, for reproof and conviction of sin, for correction of error and discipline in obedience, [and] for training in righteousness (in holy living, in conformity to God’s will in thought, purpose, and action), 17 So that the man of God may be complete and proficient, well fitted and thoroughly equipped for every good work.  2 Timothy 3:16-17 AMP

Nevertheless I tell you the truth. It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I depart, I will send Him to you. 8 And when He has come, He will convict the world of sin, and of righteousness, and of judgment: 9 of sin, because they do not believe in Me; 10 of righteousness, because I go to My Father and you see Me no more; 11 of judgment, because the ruler of this world is judged. 12 “I still have many things to say to you, but you cannot bear them now. 13 However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come. 14 He will glorify Me, for He will take of what is Mine and declare it to you.  John 16:7-14 NKJV

Fruit:
Discipline yields fruit. Righteousness is a fruit – the fruit of obedience. Fruit grows naturally only in the right conditions. You can’t force or fake fruit – you can’t make or manufacture fruit in a factory – you can only grow it. Natural growth and production of fruit, occurs on a tree or a bush that has food, light, soil, and water. Fruit trees also need to be pruned and cut back or the fruit will be weak and unhealthy. Some plants or vines need to have a frame to grow on or be attached to a straight piece of wood to make them grow straight. They are “trained” in a certain direction. We are God’s branches; attached to His vine; producing His fruit. Unless we receive the Word of God and submit ourselves to it; unless we allow the working and training of the Holy Spirit in us, we will bear no good fruit. Receiving the Father’s discipline and correction in your life will produce the fruit of righteousness in you.  

Righteousness:
The fruit or result of discipline is righteousness. The fruit of righteousness is produced in those who are trained by God’s discipline – not in those who resist God’s discipline and correction.

Peace:
If you are rebellious, you will have no peace and no rest. When you submit to God’s discipline and allow Him to correct you and train you, the peaceable fruit of righteousness is the result. Discipline produces righteousness; righteousness produces peace.