Spare the rod, spoil the child

लालनाद्बहवो दोषाः
ताडने बहवो गुणाः ।
तस्मात्पुत्रं च शिष्यं च
ताडयेन्न तु लालयेत् ॥

- चाणक्यनीतिः

Pampering leads to many bad habits, whereas chastisement results in many good habits. Therefore, one should discipline his child or pupil without showing excessive indulgence.

Spare the rod, spoil the child.