It is only our conviction in His existence that makes us actually feel Him. It is well corroborated by the story of Hiranyakashipu asking his son Prahlad “where is your Narayan?” The boy says that He is omnipresent. The father is not convinced and asks him specifically if Lord is there in a sizzling pillar standing in front of them. As the son replies yes he is asked to touch it. Prahald ji spontaneously embraces the hot pillar but nothing hurts him. This convinces Hiranyakashipu that Narayan is surely present in the pillar due to which Prahalad is unharmed. So he strikes on it with a motive to hit Narayan and then lord Narsimha indeed appears. Hence it can be said that Lord appeared out of his conviction.