Is it truly wrong to calculate that by doing good i’ll create good in my life?

Holy book is not wrong, it is right and absolutely correct. A Master must state the truth, the associated benefits of being good or nice to others and he is doing that but people who are listening to that are not ordinary people. These truths were told by Jesus to chosen few – those 10-12 disciples. These were the one’s who were genuinely interested in teachings. These select few were real seekers and interested in the Truth rather than their business. These people probably could understood his teachings, rest did not otherwise why would he crucified at all?