פירוש על קהלת 4:11

They can be warm. [To be understood] according to its apparent meaning, regarding male and female, who are aroused by one another and procreate.¹⁶Alternatively, these verses refers to the performance of a mitzvah, i.e., if each one performs a mitzvah on his own then if he slackens off, there is no one to encourage him and “uplift him.” However, when two people perform a mitzvah together, it adds “warmth” to their performance of the mitzvah. (Divrei Avrohom)