Is a neighbor lawfully entitled to seize a portion of the land irrigated by the existing irrigation machine, given that irrigation regulations prohibit the presence of two machines and the current machine does not refuse water to anyone, and would the owner of the existing machine be sinful for filing a legal complaint against him?

It is a person's right to set up their own irrigation machine on their land, even if their neighbor has another machine. This is because they are acting within their property rights and have various interests. The custom in some countries may prohibit watering others, but this is not considered valid, for "provision is apportioned," and it does not prevent selling or renting. If the state prohibits multiple machines for a clear public interest, then compliance is obligatory; otherwise, it is not. There is no blame on one who sets up a machine on their land to water themselves or others, as that is an act within their private property for their benefit, without causing considerable harm to others.