Discipline is a key to a successful Christian life.
1 Timothy 4:12-16 Let no one despise their youth; but be an example of the believers, in word, in conversation, in charity, in spirit, in faith, and in purity. Till I come, give attendance to reading (The Bible), to exhortation, to doctrine. Do not neglect the gift that is in you.
II Timothy 1:7 God has not given us the spirit of fear; but of power and of love, and of a sound mind.
II Timothy 2:15, Proverbs 10:4, 1 Corinthians 9:27