Question: I know that 1 Timothy:2:10 says that "...prayers, intercessions, and giving of thanks, be made for all men" But my question is: since no one can be forced to get saved without their choosing Jesus as their Savior for themselves, what does praying for the lost do? I heard one man say, "My family prayed for me to get saved for 26 years," etc., but since their prayers didn't force him to trust Christ, nor did it force God to save him against his will, what's the practical use of it, other than it being a command here from the Apostle Paul?
Response: Your question would be even more puzzling if you added the fact that God is omniscient and has known from eternity what a person will pray, how He will answer the request, and what the results will be regarding the person for whom the prayers are being offered. Although that doesn't help us to fully comprehend how prayer works, it does show us that the value of prayer is for man and not for God. What are the values? When we pray to God, we communicate with Him, and if our prayers are earnest, they involve faith: "He that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him" (Heb:11:6). As we see our prayers answered, we grow in our faith and relationship with God. The more we pray, the more we see Him at work in our lives. The more things we pray about, from the little things to the seemingly impossible things, the more we see His consideration of all aspects of our lives.
What then does that have to do with praying for someone who must, of his own free will, put his faith in Jesus? God already knows who will put their faith in Him and who will not. Prayer will not change the latter, but it will have a tremendous effect on the person who eventually comes to Christ. Ask any of those Christians who knew that believers were praying for their salvation before they were born again. Most of them will say, upon looking back, that they saw God's influence in their lives.
First Timothy 2:10 is not just "a command from the Apostle Paul," as if it were only Paul's considered opinion. In writing about the inspiration of Scripture, Peter identified Paul's writings as "Scripture" (2 Pt 3:16) and also said in 2 Peter:1:21, "For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost."
Consequently, it is the Lord's directive that we pray for the lost. Paul's obedience to this command was clearly seen when he wrote, "Brethren, my heart's desire and prayer to God for Israel is that they might be saved" (Rom:10:1). Paul knew that though there is coming a time in which "all Israel shall be saved" (11:26), he no doubt recognized that he was unlikely to see that day in his lifetime. Nevertheless, he prayed. Paul's heart was revealed when he wrote, "For I could wish that myself were accursed from Christ for my brethren, my kinsmen according to the flesh" (9:3).
Additionally, the context of the passage that you quote suggests that we not only pray for "kings, and all that are in authority" in general terms but in order to fulfill the will of God, "who will have all men to be saved, and to come unto the knowledge of the truth" (v. 5). Obedience is the first "practical" fruit of prayer. (If for no other reason, it may be that prayer changes our spiritual posture as much as it changes anyone or anything else.) But as far as how prayer works as an evangelistic tool, we have little information on which to base any scientific inquiry. It is certainly not based in the inherent "power" of words or vain repetition, for that is occultism (Mt 6:7). However, we know that praying for "all men"—even for those who persecute us and despitefully use us (Mt 5:44)—is in accordance with God's will. And what greater prayer can we offer than the request that God may grant such men (and women) repentance, which is His stated desire throughout Scripture (Jn:3:17; 2 Pt 3:9). Conversely, Satan seeks to disparage prayer and discourage its use.
So, while we are shielded from the understanding of how prayer "works" in the spiritual realm, we do know that it is a true weapon of warfare (2 Cor:10:4), as Scripture affirms: "The effectual fervent prayer of a righteous man availeth much" (Jas 5:16b). Fortunately, the effectiveness of our prayer is not dependent on our flowery speech or persuasive words (Ex 4:10, 2 Cor:10:10) but is carried to the throne by the Holy Spirit, who "helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered" (Rom:8:26).
As countless testimonies of individuals affirm—even of those who have been lost for decades and may have at one time spit in the face of God (and of those praying for their salvation)—prayer does work. And while neither prayer nor the Holy Spirit can "force" anyone to receive the truth, it is evident that they work together with the living Word of God (Eph:6:17-18, Heb:4:12) to grant opportunity for spiritual discernment and understanding to all "natural men" (1 Cor:2:14, Jas 1:23). Thus praying for others is not a form of spiritual manipulation, but an act of love, out of concern for the eternal destiny of human souls, in accordance with the will of God.
Finally, regarding the man whom you mentioned whose family had prayed for him for 26 years, God's answers are not held to a time limit. My wife and I prayed for a relative for more than 20 years. It was only over time that the Lord's circumstances broke down her idols, played upon her heart, and brought her to the place where she cried out to the Lord for salvation. How many of those circumstances came in answer to prayer? We can't answer that, but we do know that the consistent message of Scripture is that we are to pray and that God answers all prayers, in His way and in His time.