Some people have the impression that Christianity tells people to pray for those who are sick or in need at the expense of doing something practical about their needs. This impression is incorrect in two ways: its substance is incorrect, for the Bible teaches us to act as well as to pray, but it also mistakenly assumes that prayer is ineffective.
The Bible emphasizes putting one's faith into action by doing good deeds, not just thinking nice thoughts or saying nice things:
If anyone has material possessions and sees his brother in need but has no pity on him, how can the love of God be in him? Dear children, let us not love with words or tongue but with actions and in truth. (1 Jn 3:17-18)
Suppose a brother or sister is without clothes and daily food. If one of you says to him, "Go, I wish you well; keep warm and well fed," but does nothing about his physical needs, what good is it? In the same way, faith by itself, if it is not accompanied by action, is dead. (James 2:15-17)
Jesus' life and teaching included both prayer and action. Presumably, if God meant for us to spend all of our time praying, Jesus would have spent all his time praying for people instead of going out to help and teach them. Although Jesus devoted plenty of time to prayer, it was not the only thing he did. In fact, he taught that we should not pray long redundant prayers in an effort to be heard by God or impress others (Mt 6:7-8, Lk 20:47).
Why then does the Bible emphasize prayer? Why would prayer do any good? By praying, we are asking the omnipotent and loving God of the universe to intervene and provide help to those who need it; he is both able and willing to answer these prayers (Mt 7:7-11). When God waits for us to make a request and then responds to it, rather than fulfilling the need before we ask, he is interacting with us and teaching us about himself: that he does love us and care for our needs, and that he is faithful and will respond to us when we ask him for what is good.