Jesus said to his disciples, «Say yes when you mean yes and say no when you mean no».
Today Jesus goes on talking about respect for others. Do we want to love? Then we must take care of the language ("how we say things") and the truth ("what we say"). Sometimes in our environment we hear some nonsense like the following: "I swear it by my ancestors" (or similar expressions). Whoever swears too much is because he lies too much!
— Do you want to be loved? Keep your word! As Jesus recommends, "do not swear by Heaven (...), nor by the Earth ... nor by your head", because you do not even know how many hairs you have on it.