The whole sentence means: don't carry heavy things when you are weak, and don't persuade others when you speak without weight. Don't be as extravagant as others if you don't have enough money, and don't look for relatives if you have difficulties.
These words are exhortations to remind people how to deal with different situations. For those who are weak, don't add too much burden to yourself, and don't convince others if your words have no influence, so as not to cause unnecessary trouble. If you don't have enough money, don't blindly follow the trend and pursue luxury. When you are in trouble, don't ask your relatives for help, so as not to deepen your predicament.