The fierce form of Lord Nṛsiṁhadeva may appear most awful to a non-devotee, but to the devotee the Lord is always affectionate as He is in other forms. Conditioned life in the material world is actually extremely fearful; indeed, a devotee is not afraid of anything else. Fear of material existence is due to false ego. Whether one is a devotee of the Lord or is a non-devotee does not depend upon one’s birth in a high or low family. Even Lord Brahmā and the goddess of fortune cannot achieve the full favor of the Lord, whereas a devotee can very easily attain such devotional service. The Lord’s mercy is bestowed equally upon everyone, regardless of whether one is high or low. Because Prahlāda Mahārāja was blessed by Nārada Muni, Prahlāda became a great devotee. The Lord is present in everyone’s heart as the Supersoul to give the living being protection and all benefits. Thus the Lord acts sometimes as the killer and sometimes as the protector. One should not accuse the Lord for any discrepancies. It is His plan that we see varieties of life within this material world. All of them are ultimately His mercy.
Ref >> Srila Prabhupada Vani.