http://revach.net/article.php?id=2628

Section: Parshas HaShavua   Category: Quick Vort
Parshas VaEschanan: Rav Yisroel Salanter - When Hints Will Suffice
 לֵךְ, אֱמֹר לָהֶם:  שׁוּבוּ לָכֶם, לְאָהֳלֵיכֶם  We find before Mattan Torah, when Hashem told Klal Yisrael to separate from their wives, He said a direct and explicit command," Al Tigshu El Isha - Do not come close to a woman."  However, when He told them to return to their wives after Mattan Torah, it was only hinted to them with the words, "Shuvu Lachem L'Ahalaychem; Return to your tents,"

R'Yisrael Salanter says, "We see from here, when telling someone that something is prohibited, you must spell it out to the person in a clear and concise language. A hint will not suffice, since he just won't get it. However, when it comes to a Heter, telling someone that something is allowed, a person will understand what you mean even with the most vague hint! That is why when it came to tell Klal Yisrael that they must separate from their wives it was said explicitly. However, when it came to be allowed again to their wives the words  שׁוּבוּ לָכֶם, לְאָהֳלֵיכֶם sufficed."