Unanswered Prayers

I am reminded through the reading of Prayer: Does It Make any Difference? by Philip Yancey (Zondervan) of some of the reasons we pray and seem to get no answer.

One verse that is quoted in Chapter 16 Unanswered Prayer: Whose Fault? is the following from
Proverbs 21:13 (NIV) "If a man shuts his ears to the cry of the poor, he too will cry out and not be answered." Yancey makes the following statement: "Thus God flatly declares that, in addition to our private spiritual state, our social concern (or lack of it) - for the poor, for orphans and widows - also has a direct bearing on how our prayers are received."

The subject of unanswered prayer is so broad and so deep that man can and has written volumes to address the topic. I realize that there is no "magic" formula to prayer to ensure the answer I desire, even though there seems to be numerous people who would tell me otherwise. I am reminded, however, that there are some things God expects me to do for others - things that are indicators of whether my prayers are driven by my own selfish desires or for the advancement of God's will.

Can this really be true?

Consider the words of Jesus from Matthew 25:41-45 (The Message)
41 -43"Then he will turn to the 'goats,' the ones on his left, and say, 'Get out, worthless goats! You're good for nothing but the fires of hell. And why? Because— I was hungry and you gave me no meal, I was thirsty and you gave me no drink, I was homeless and you gave me no bed, I was shivering and you gave me no clothes, Sick and in prison, and you never visited.'
44"Then those 'goats' are going to say, 'Master, what are you talking about? When did we ever see you hungry or thirsty or homeless or shivering or sick or in prison and didn't help?'
45"He will answer them, 'I'm telling the solemn truth: Whenever you failed to do one of these things to someone who was being overlooked or ignored, that was me—you failed to do it to me.'