《汉书·传·宣元六王传》
因为是老朋友的恩情，还容忍他的小缺点，更何况是这样的骨肉之情呢！
夫以故旧之恩，犹忍小恶，而况此乎！
As it's the favour of an old friend, you should tolerate his petty flaws. So how much more so when it comes to the bond of blood that we share?