Musar על סנהדרין 3:14

An example of how the number "ten" is relevant in דינין is the composition of the collegium of judges that can adjudicate capital crimes. The total number of judges required is twenty three. This is arrived at in the following manner. The Torah writes in Numbers 35,24, and 25, ושפטו העדה … והצילו העדה. This means that there has to be an עדה, i.e. ten people who are capable of voting innocent, whereas there also has to be a מנין who are capable of voting guilty. Since the Torah demands a minimum majority of two judges in order to make a "guilty" verdict legal, we have to add another two judges to the twenty we have just mentioned. Since we must avoid a "hung jury," a third judge is added to provide us with an odd number as the total (No judge is allowed to abstain). We have seen that the number "ten" is significant then both as "ten" and as "twenty," i.e. the "ten" spelled as יוד that we mentioned previously.