These verses from the book of Matthew give us a fairly explicit idea of how God commands us to treat each other, with particular emphasis on those who are suffering.
When the Son of Man comes in his glory, and all the angels with him, he will sit on his glorious throne. . .
Then the King will say to those on his right, ‘Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world. For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.’
Then the righteous will answer him, ‘Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? When did we see you a stranger and invite you in, or needing clothes and clothe you? When did we see you sick or in prison and go to visit you?’
The King will reply, ‘Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me.’ "
Clearly, when a population of people is suffering, for whatever reason, whether it be a natural disaster such as the earthquake and tsunami in Japan, or a less dramatic, but nonetheless unhappy suffering of homeless or hungry in America (or anywhere), it is pretty clear that if we serve the suffering, we are also serving God. Conversely, if we do not serve those who need it most, we are doing no less than turning our backs on God as we turn our backs on them.