Сачковать - is sort of rude word / means to avoid something difficult like work / if i were you i wouldn't use this word. Пахать - is a synonym of to work hard , literelly to plow / I never have heard this Russian saying

I don't think that it's a proverf and yes it is very unformal, you can use this frase only with friends, for example. It means that of course working hard is not the same that lying on the couch

прямое значение - пахать землю (پاشیدن زمین) значение здесь - тяжело работать (کار کردن) сачковать - از بین بردن "Пахать, не сачковать!" - так может сказать добросовестный работник лодырю, который работает плохо и старается увиливать.

Правильно)

That means you have to work instead of the relaxation while you're supposed to work. If you are lying on the beach while you have to work then you САЧКУЕШЬ (Сачковать)