A few days ago, you said that we should not give bribe to God to get anything from him. In Hinduism, we do Mannat, wherein we pray to God for something and in return we give him something. Is this justified?
Doing Mannats are for your own sake. God’s grace is unconditional (Ahetu Ki Kripa). God gives things to you unconditionally.
These are just practices. They don’t have any basis in the scriptures. If you do good seva, it gives you good merit, and merit brings you happiness.