strength in numbers?
Birds of a feather flock together?
this one
The Bundle of Sticks
An old man on the point of death summoned his sons around him to give them some parting advice. He ordered his servants to bring in a ****** (Yahoo's filter will not allow this word to be printed. In the past it was perfectly acceptable) of sticks, and said to his eldest son: "Break it." The son strained and strained, but with all his efforts was unable to break the Bundle. The other sons also tried, but none of them was successful. "Untie the *******," said the father, "and each of you take a stick." When they had done so, he called out to them: "Now, break," and each stick was easily broken. "You see my meaning," said their father.
Union gives strength.
There are several versions of this idea running throughout history. Another example is in the Bible, Ecclesiastes 4:12 “And if one prevail against him, two shall withstand him; and a threefold cord is not quickly broken.