This is an idiom that means they should pay attention. AT: "Listen carefully and remember" or "Do not forget this" (See: [[rc://en/ta/man/translate/figs-idiom]])
This can be stated with an active clause. Here "hands" refers to power or control. AT: "they will betray the Son of Man and put him in the control of men" (See: [[rc://en/ta/man/translate/figs-activepassive]] and [[rc://en/ta/man/translate/figs-metonymy]])
Jesus does not identify these men here, but it might be helpful to state that information. AT: "to my enemies" (See: [[rc://en/ta/man/translate/figs-explicit]])