Русско-английский словарь пословиц и поговорок
ТЯЖЕЛО В УЧЕНИИ, ЛЕГКО В БОЮ
Knowledge and skill acquired by hard work will be of great help in difficult times. See Ученья корень горек, да плод сладок (У)
Cf:Lessons hard to learn are sweet to know (Am.,Br.). They that sow in tears shall reap in joy (Am.)