Can we really be altruistic when we know there's a reward coming up?

The first Baraita in the sixth chapter of Avot praises the person who learns Torah for its own sake and not for any personal advantage or ulterior motive. After saying in general terms that, for such a person, the world is his oyster, it lists some 29 praises, virtues and attributes with which this good soul is garlanded: these include wisdom, power, glory, integrity and (this is handy in today's difficult world) an ability to forgive insults. 

It may seem strange that all the wonderful virtues and praises listed in this Baraita come only to someone who does not learn the Torah in order to acquire them even though, as a student of the Torah, he knows that they will inevitably come to him. This conundrum is similar to the conceptual basis for one of the earliest mishnayot in Avot (1:3), which teaches that we should not serve God in order to obtain a reward — even though we know full well that a reward automatically follows our service. 

In our lives we all face this situation in one form or another when we have the opportunity to do things that benefit us but we nonetheless do them for the sake of another. A typical situation in which this may happen is where a parent seeks to calm a screaming baby at three o’clock in the morning: while the parent knows that he or she will not be able to return to bed until the baby is placated, parental feelings of love, concern and empathy for the baby’s unarticulated anguish may completely swamp any selfish feelings of self-interest. This is the altruistic basis upon which we should seek to serve God and — as this Baraita indicates — the way we should seek to learn Torah.