When we pray, God hears. 2 Samuel 22:7 "In my distress I called upon the LORD; to my God I called. From his temple he heard my voice, and my cry came to his ears."
God hearing should motivate us to further prayer. Psalm 116:1-2 "I love the LORD, because he has heard my voice and my pleas for mercy. Because he inclined his ear to me, therefore I will call on him as long as I live."
The church prayed earnestly for Peter's release. Acts 12:5 "So Peter was kept in prison, but earnest prayer for him was made to God by the church." And if you read the following verses you'll find the story of his release.
Praying is striving with the one for whom you're praying. Romans 15:30 "I appeal to you, brothers, by our Lord Jesus Christ and by the love of the Spirit, to strive together with me in your prayers to God on my behalf."
We help others and bring them blessing by praying for them. 2 Corinthians 1:11 "You also must help us by prayer, so that many will give thanks on our behalf for the blessing granted us through the prayers of many."
The prayer of the righteous is powerful. James 5:16b "The prayer of a righteous person has great power as it is working."
So, will you take some time to get to your church's prayer meeting and labor along side of those for whom you're praying? Will you get in your prayer closet and help someone by praying for them? It won't be a waste of time and may well be the most useful thing you could do for them.