:Ramana maharshi :
Many afflictions, like thunderbolts, heavily oppress excellent and virtuous devotees. You should know that this happens not to torment them but to firmly establish and make resilient [in tapas] the minds of those pure ones.
Guru Vachaka Kovai v 617.
Without his excellent mind losing its composure, let the sadhaka endure to the very end the tribulations that come to him through prarabdha. He should understand that they [the tribulations] are God’s blessed grace which enables him to attain divine fortitude. They have as their ultimate purpose the bestowal of liberation on the mature soul.
Guru Vachaka Kovai v 618.
Question: How is it that so much suffering comes to people who behave virtuously?
Bhagavan: It is good if suffering comes to devotees. The dhobi [washer man], when washing clothes, beats them hard against a rock. But he does so only to remove the dirt from the clothes. Similarly, all sufferings are given for the sole purpose of purifying the mind of the devotee. If we are patient, happiness will follow.
An uncut gem excavated from a mine will not attain brilliance unless it is cut and polished. Similarly, the true tapas, the sadhana that a sadhaka performs, will not shine except by the ordeals which are the obstacles to it.