Answer
We know that current is the rate of flow of charge. In any circuit, at any node, if net current entering is not zero, it means that with time charge builds up at the node.
Work Step by Step
We know that current is the rate of flow of charge. In any circuit, at any node, if net current entering is not zero, it means that with time charge builds up at the node. And similarly at another node charge builds up, and if this happens they attract or repel each other and circuit will get distorted, which doesn't happen, which means at any node net current entering is zero.
At any node in any electrical circuit net current entering it is zero.This is KCL(Kirchhoff's Current Law).