Read Ecclesiastes 4:12 Using Other Translations
And if one prevail against him, two shall withstand him; and a threefold cord is not quickly broken.
And though a man might prevail against one who is alone, two will withstand him--a threefold cord is not quickly broken.
A person standing alone can be attacked and defeated, but two can stand back-to-back and conquer. Three are even better, for a triple-braided cord is not easily broken.