Every man carries two bags about him, one in front and one behind, and both are full of faults. The bag in front contains his neighbors' faults, the one behind his own. Hence it is that men do not see their own faults, but never fail to see those of others.
AesopA farmer who had a quarrelsome family called his sons and told them to lay a bunch of sticks before him. Then, after laying the sticks parallel to one another and binding them, he challenged his sons, one after one, to pick up the bundle and break it. They all tried, but in vain. Then, untying the bundle, he gave them the sticks to break one by one. This they did with the greatest ease. Then said the father, "Thus, my sons, as long as you remain united, you are a match for anything, but differ and separate, and you are undone".
Aesop