"Beware of practising your piety before others in order to be seen by them; for then you have no reward from your Father in heaven. [...] And whenever you fast, do not look dismal, like the hypocrites, for they disfigure their faces so as to show others that they are fasting. Truly I tell you, they have received their reward. But when you fast, put oil on your head and wash your face, so that your fasting may be seen not by others but by your Father who is in secret; and your Father who sees in secret will reward you."
- Matthew 6.1, 16-18 (NRSV).Does fasting earn spiritual brownie points? Does every meal skipped now give us an extra helping at the messianic feast of the age to come? I don't think that this is Jesus' point here. He is warning against those whose acts of piety (he mentions charitable giving, prayer and fasting) are done in order to be seen by others. Jesus has no problem with good deeds that are visible to others. Indeed, just a few verses earlier, he taught his listeners to "let your light shine before others, so that they may see your good works and give glory to your Father in heaven" (Matthew 5.16, NRSV). The issue here is not the visibility of the works, but their purpose. Ostentatious display somehow undermines the point of such deeds, which suggests that their point has to do with our hearts, with our motives and desires (a conclusion also suggested a few verses later in 6.19-21, where Jesus speaks of what it is that our hearts treasure). We give, pray and fast in order to allow our hearts to be shaped by such disciplines. These activities are done for the healing of our desires not the enhancement of our reputation. At least part of the reward of fasting, then, is to discover that our treasure is indeed heavenly and so free from the vicissitudes of material possessions or social reputation.
"Heaven" in Matthew's Gospel is not code for eschatological promise (as it is often misused in much Christian discourse), but is either a reference to God's dwelling place (5.34, 14.19 and all occurrences of "Father in heaven"), or a synecdoche for God himself (3.17, 16.1, 18.18, 21.25 and all occurrences of "kingdom of heaven"). In other words, when Jesus speaks of storing up treasure in heaven, he is not first and foremost talking about the future (unlike, say 1 Peter 1.4, though even there the hope is that it will be revealed, not that we will go to heaven to be with it). Instead, storing up treasure in heaven means cherishing God, seeking first his kingdom and his righteousness. It means a transformation of our desires so that we are not seeking our own glory but delighting in God's. And this is why any attempt to gain credit before others through acts of piety destroys the very purpose of those acts, since it distracts us from the chance to have our desires realigned towards God and his purposes.
Therefore, perhaps the "reward" of fasting (or prayer or giving) that Jesus refers to in Matthew 6 is not that we somehow earn a better future, but that our desires take another step on the path to healing, that we are slowly liberated from our crippling self-obsession. This is no mercenary bonus, unrelated to the activity that wins it. It is the appropriate outcome of the very activities that seek to draw us out of the echo chamber of own hearts. Our reward might well be that we become a little more capable of love.
I have tried head off one potential misunderstanding of this post at the pass.