Question: Is there any difference between the happiness and distress caused by karma and the happiness and distress that are caused by the Lord’s mercy in terms of “sense” or the “taste” level of that experience? On the “cause and effect” level, you have already explained that non-devotees get happiness or distress according to their past pious or impious deeds, and have a good or bad result respectively, but the devotees get happiness and distress as the Lord’s mercy with the purpose to intensify their love to the Lord. Do devotees experience the “same” sense of such duality (happiness and distress) as the non-devotess or how does it differ?
Answer: There is no difference in the mechanism of experience of happiness or misery of a devotee or non-devotee. A devotee, like a non-devotee, also experiences through his/her senses. Both have five external senses and mind. The difference lies in the reaction of one’s experience. A devotee sees everything as grace of Lord, an opportunity to learn, advance and become stronger. He/she may see it as an act of purification. He/she will stay composed and fixed in his/her service. You can read the stories of the Pandavas or some contemporary devotees to see how a devotee takes his happy and miserable situations.
Question: If nitya-siddha devotees who appear in this material world according to the Lord’s will don’t have any sense of material duality because they are always absorbed in the Lord’s ananda, how could they know about the jiva’s miseries (and help them to get liberated) if they are not even aware or haven’t experienced the existence of such miseries?
Answer: If they have not experience material suffering themselves ever, then it is not possible for them to empathize with other’s suffering.
Nitya-siddhas like the Pandavas are a part of Lord’s lila. They are not under the influence of maya but seem to appear like that. Even Krishna most of the time appeared as if He was under the control of maya but He also showed that He was not.