Recent work identified a shift in judgments of moral praiseworthiness that occurs late in development: adults recognize the virtue of moral actions that involve resolving an inner conflict between moral desires and selfish desires. Children, in contrast, praise agents who do the right thing in the absence of inner conflict. This finding stands in contrast with other work showing that children incorporate notions of cost and effort into their social reasoning. Using a modified version of Starmans and Bloom's (2016) vignettes, we show that understanding the virtue of costly moral action precedes understanding the virtue of resolving inner conflict. In two studies (N = 192 children, range = 4.00-9.95 years; and N = 193 adults), we contrasted a character who paid a personal cost (psychological in Study 1, physical in Study 2) to perform a moral action with another who acted morally without paying a cost. We found a developmental progression; 8- and 9-year-old children and adults recognized the praiseworthiness of moral actions that are psychologically or physically costly. Six- and 7-year-old children only recognized the praiseworthiness of moral actions that are physically costly, but not actions that are psychologically costly. Moreover, neither adults nor children inferred that paying a cost to act morally required having a moral desire or resolving inner conflict. These results suggest that both adults and children conceptualize obligation as a direct motivational force on actions. They further suggest that costly choice-a hallmark of moral agency-is implicated in judgments of praiseworthiness early in development.