Summary: When a Christian prays, God is pledged to act. This is especially true when we pray for fellow Christians who have begun to stray.
“This is the confidence that we have toward him, that if we ask anything according to his will he hears us. And if we know that he hears us in whatever we ask, we know that we have the requests that we have asked of him.
“If anyone sees his brother committing a sin not leading to death, he shall ask, and God will give him life—to those who commit sins that do not lead to death. There is sin that leads to death; I do not say that one should pray for that. All wrongdoing is sin, but there is sin that does not lead to death.” 
What is the one answer to a prayer you presented before the Master that looms large in your memory? Take a moment and write it down. Tragically, many listening will not be able to write anything down. What is the most recent answer to prayer that you can recall? I mean, what specific request did God answered and you know it was because you asked? Again, I fear that many who listen will not be able to recall an answer.
Let’s face it, few Christians could be convicted of praying excessively! We say prayers, but we seldom pray. I mean that we will fling a perfunctory plea heavenward, but not often do we engage in prevailing prayer. We Christians struggle to stay engaged in prayer. We know that we should pray, and we even have the desire to pray as the Spirit of God prompts us to pray. However, prayer is hard work, and we are often overwhelmed by the needs before us. Of course, it is easy to say that we should not pray in our own strength, but that we should pray in the power of the Spirit. The words flow easily from our lips, but the work is considerably more demanding.
It is not the purpose of the message today to condemn anyone for a lack of prayer. This is not one of those simplistic messages with “5 easy steps in prayer.” I make a continual effort to call your names before God’s eternal throne. I am often prompted by the Spirit to pray for your burdens of which you have informed me. It is not unusual that I am awakened in the night by the urging of the Spirit to call your name and to mention the needs you have expressed. Yet, I know that I do not pray as often or with the perseverance that should mark a child of God.
I see the Apostle admonish the saints, “Pray without ceasing” [1 THESSALONIANS 5:17], and I know that I have failed. I realise that the Master taught that His disciples “ought always to pray and not lose heart” [LUKE 18:1], and I am chagrined by the knowledge that His teaching condemns my failure. Please, do not imagine that I am speaking from some superior position to censure you; I am speaking today as a mere man who longs to do the will of God. Before ever Ezekiel spoke, he sat where those whom he would address were dwelling—he sat overwhelmed among them [see EZEKIEL 3:15]. In similar fashion, my message comes from sitting where you sit. My words are not meant to condemn; they are meant to instruct, to equip, to strengthen.
In the text before us, the Apostle of Love makes a startling statement when he testifies, “If we know that he hears us in whatever we ask, we know that we have the requests that we have asked of him” [1 JOHN 5:15]. Twice does he speak of the certainty that marks the Christian. Admittedly, he couches the first statement of confidence in what could be thought a conditional form; however, when read in context with the second assertion of confidence, it is obvious that John is making a statement concerning the confidence that marks the Christian.