Ambition is sometimes viewed negatively. Godly ambition, on the other hand, is something every Christian should cultivate. John R. W. Stott has hit the nail on the head in his book, "The Message of the Sermon on the Mount":
"Everybody is ambitious to be or to do something, often from early years. Childhood ambitions tend to follow certain stereotypes - e.g. to be a cowboy, astronaut or ballerina. Adults have their own narrow sterotypes too - e.g. to be wealthy, famous or powerful. But ultimately there are only two possible ambitions for human beings... just as there are only two kinds of piety, the self-centered and the God-centered, so there are only two kinds of ambition: one can be ambitious either for oneself or for God. There is no third alternative.
"Ambitions for self may be quite modest (enough to eat, to drink and to wear, as in the Sermon) or they may be grandiose (a bigger house, a faster car, a higher salary, a wider reputation, more power). But whether modest of immodest, these are ambitions for myself - my comfort, my wealth, my status, my power.
"Ambitions for God, however, if they are to be worthy, can never be modest. There is something inherently inappropriate about cherishing small ambitions for God. How can we ever be content that he should acquire just a little more honour in the world? No. Once we are clear that God is King, then we long to see him crowned with glory and honour, and accorded his true place, which is the supreme place. We become ambitious for the spread of his kingdom and righteousness everywhere."