Why should the funeral prayer be offered in an odd number of rows?

It is not an obligation but a recommendation. Islam prefers odd numbers because God is One, and at the funeral prayer this preference is easy to put into practice.

First, the most important point. A funeral prayer is valid even if the number of rows is even. No one commits a sin when it cannot be arranged otherwise. This is a recommendation, not a command.

The reason lies in a preference that runs through the whole of Islamic practice. God is One, and the Holy Prophet Muhammad (saw) taught that He loves odd numbers. That is why Islam prefers odd numbers wherever this is possible. Often it goes unnoticed.

Daily prayer is one example. There are five prayers a day, an odd number. Most of the obligatory prayers consist of an even number of units, and only the evening prayer has an odd number. Because of this, the total of all obligatory prayers becomes odd. The voluntary prayers are similar. They come in units of two or four, but at the end of the day the Witr prayer is added, and again the total becomes odd.

Why then does the recommendation apply only to the funeral prayer and not to the daily congregational prayer? At the daily prayer people keep arriving and joining the rows. It would hardly be possible to control the number of rows without disturbing the prayer. A funeral prayer, on the other hand, is a special occasion. One can wait a little until everyone has arrived and then arrange the rows. It is usually held in the open, and latecomers can simply join at the sides.

In this way a small and beautiful reminder of God's Oneness is kept where it causes no one any difficulty.