"Rabba said, the lulav in the right hand and the etrog in the left. What is the reason? These constitute three mitzvoth, and this [etrog] is one mitzvah. This can be understood to mean that the Gemara asks, "What is the reason for holding the etrog in the left hand?" Does the etrog not represent the complete Torah scholar, as we mentioned, and is the finest of all, in that it has taste and aroma? Isn't it more appropriate to hold it in the right hand? This is the Gemara’s reply: The lulav constitutes three mitzvoth – lulav, hadas and 'arava – while the etrog represents a single mitzvah, which gives them precedence over the etrog.
The Gemara seeks to indicate that if the complete Torah scholar, who has all the good attributes, does not carry the community's householders and common folk along with him – meaning the scholar does not give classes to the congregation - even if that person is great, the lulav which is lesser is preferable, for it carries the hadas and 'arava with it.