According to which two hexagrams did this sentence be introduced?

The first eight diagrams in Zhouyi, Bi Gua, are behind and opposite to Shi Gua. "No discord, no concord" comes from here. After the fierce war, there has been a state of "shaking hands and making peace" and "meeting and laughing". Being close is a good thing. But from the perspective of Zhouyi, closeness also contains contradictions and uneasiness.

"Bi Gua" said: "It is auspicious to be close to others. When you are close, you should always stick to the right path. There is no disaster. But the unstable factors are getting bigger and bigger in intimate relationships, and the last ones who kiss are unlucky. "