Principle: The default ruling in transactions is permissibility.

The Shaykh : Let us take the principles. What is the default ruling in transactions? "The default ruling in transactions is permissibility and lawfulness". Any transaction, whether a sale, a lease, an endowment, a pledge, a deposit, a loan, or otherwise, is permissible by default. So if someone tells you, "This sale is forbidden, this lease is forbidden, this pledge is forbidden," who must provide the evidence for the claim that it is forbidden, or who must provide the evidence for the claim that it is lawful?
The student: ...

The Shaykh : The one who claims it is forbidden. I say, bring the evidence that it is forbidden. If you do, I will refrain from it and leave it alone. Otherwise, the default ruling is lawfulness.