Imaam al-Barbahaaree (rahima-hullaah) mentions:

((I will not say anything good or bad about a person until I see how he ends, after something I heard from the Prophet (sal-Allaahu `alayhe wa sallam).

It was said: ((What did you hear?))

He said: ((I heard the Messenger of Allaah (sal-Allaahu `alayhe wa sallam) say:))

((The heart of the son of Aadam is agitated more severely than the cooking pot when it boils)).

Reported by Ahmad, al-Haakim and Ibn Abee 'Aasim in ((as-Sunnah)) No.226. Declared saheeh by Shaykh al-Albaanee in ((Saheehul-Jaami')) No.5023

Sharhus-Sunnah - Imaam al-Barbahaaree

Ref: Fatwa-Online

Ibn Qudaamah al-Maqdisee said:

"You should know that the child is a trust upon his parents, his heart like an innocent gem that is open to any inscription upon it. So, if the child is accustomed to righteousness then he will develop and grow in it, and his parents and guardians will share with him the reward of living a pious and righteous life."

Ref: The Advice of the Salaf Regarding the Early Upbringing of the Child - 1