Stratagems may be used upon maaser sheni. How so? A person may say to his adult son or daughter, [or] to his male or female Hebrew slave: “Here are these coins for you, and redeem for yourself this maaser sheni.” But he may not say this to his son or daughter who are minors, or to his Canaanite male or female slave, since their hand [i.e., power] is like his hand [i.e., power].