"Those who break their word, those who break their word" comes from Mencius, Hui Liang and Wang Xia, which is also the origin of this idiom.
People who are not around you, on the contrary, also mean that people will treat you as you treat them.
Nowadays, people often use estoppel to describe a person who said something, did something, and then went back on his word, which means that his words and deeds are contradictory; Willful.
Keep your promise.