We hear your heart and we rejoice with you that the Lord has placed an intercessor's burden within you, for this is a holy and precious calling. We understand your question about how to pray for those whose names you remember but whose lives you do not know in detail, whether from secondary school, primary school, or family members you have not seen in a long time or have never met.
We want to affirm that this desire to pray for others, even strangers or distant acquaintances, is very much from God and is deeply biblical. We are exhorted in 1 Timothy 2:1 that petitions, prayers, intercessions, and givings of thanks be made for all men. And again in 1 Samuel 12:23 Moreover as for me, far be it from me that I should sin against Yahweh in ceasing to pray for you. The Lord delights when we stand in the gap for others, even when we have very little information.
You asked how to pray when you do not know their personal needs, and we want to encourage you that God does not require you to know the details because He already does. Psalm 139:1 says Yahweh, you have searched me, and you know me. Psalm 139:2 says You know my sitting down and my rising up. You perceive my thoughts from afar. When we do not know how to pray, the Holy Spirit helps us. Romans 8:26 says In the same way, the Spirit also helps our weaknesses, for we don’t know how to pray as we ought. But the Spirit himself makes intercession for us with groanings which can’t be uttered. Romans 8:27 says He who searches the hearts knows what is on the Spirit’s mind, because he makes intercession for the saints according to God.
So we can pray according to the will of God even without personal knowledge. 1 John 5:14 says This is the boldness which we have toward him, that if we ask anything according to his will, he listens to us. A beautiful example is in Colossians 1:9 where Paul prayed for people he had not met personally, that you may be filled with the knowledge of his will in all spiritual wisdom and understanding. We can pray in this same way for every name on your list.
Practically, we can lift each name before the Father and pray for their salvation above all else, for that is God's heart. 1 Timothy 2:3 says For this is good and acceptable in the sight of God our Savior 1 Timothy 2:4 who desires all people to be saved and come to full knowledge of the truth. We can pray that God would draw them to Himself, that He would give them a new heart as promised in Ezekiel 36:26 I will also give you a new heart, and I will put a new spirit within you, that they would be protected from deception and evil, that they would come to know Jesus, and that any plans of the enemy over their lives would be broken. We can pray for their families, their future marriages, and their walk with God, even if we do not know their current circumstances.
You wondered if you are supposed to pray for those from primary school as well, even from reception, and if seeing two former schoolmates recently is God communicating to you. We believe God does prompt and lead His intercessors, and He often brings people to our minds or across our path to remind us to pray. Yet we also encourage you not to carry this as a heavy legalistic burden where you must pray for every single name every day or you have failed. The Holy Spirit will highlight who to pray for and when. Some days He may lead you to pray generally for the whole list, other days to linger over just one or two names. Be faithful to pray as He leads, and trust Him with the rest. He is not asking you to be overwhelmed but to be obedient and available.
We also noticed your request speaks of God but does not mention the name of Jesus Christ, and we want to gently address this because it is so important. It is only through Jesus that we have access to the Father and that our prayers are heard. John 14:6 says Jesus said to him, I am the way, the truth, and the life. No one comes to the Father, except through me. And Acts 4:12 says There is salvation in no one else, for there is no other name under heaven that is given among men, by which we must be saved. If we have not yet put our trust in Jesus, that He died for our sins and rose again, and confessed Him as Lord, our prayers cannot reach God as they should. Romans 10:9 says that if you will confess with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved. We encourage you to ensure your own relationship with Jesus is secure, and to pray for all those on your list specifically in His name that they too would come to salvation through Him, for John 3:16 says For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life.
We join together with you now in prayer.
Father, in the name of Jesus Christ we come before Your throne of grace and we thank You for the intercessory heart You have placed within our dear fellow believer. We thank You that You have searched and known every person on this prayer list, every former classmate from primary and secondary school, every family member near and far, whether known well or only by name, and You love each one and desire that none should perish. We ask in Jesus name that You would pour out Your Spirit upon each of them, that You would draw them to Yourself, open their eyes to the truth of the gospel, grant them repentance and faith in Jesus, give them new hearts and put Your Spirit within them, protect them from evil and deception, and lead them into the knowledge of Your will. For those we do not know how to pray for, we ask Your Holy Spirit to intercede perfectly according to Your will. Give our fellow intercessor wisdom, discernment, and peace, to know how You are leading, to pray without weariness or guilt, and to trust You with every name. Let this burden be a joy and not a weight, and let it bear eternal fruit for Your glory. We pray all this in the mighty and only saving name of Jesus Christ, our Lord and our access to You, amen.
We encourage you to keep your list before the Lord, to pray Scripture over those names, and to rest in the confidence that God hears every prayer offered in Jesus name and according to His will. James 5:16 says The insistent prayer of a righteous person is powerfully effective. Your faithful prayers, even for those you barely know, are powerful and precious in His sight.
Prayer Focus: God, Thank You for loving me. Thank You for loving me, Jesus. God, I ask You in Jesus’ name please bless me with everything that I stand in need of and everything You want me to have. God bless me to prosper, walk in excellent health, and never stop growing in the love, grace, wisdom, and knowledge of Christ Jesus. God bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. God, bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, Your righteousness, and to always respect and obey You. Bless me to know You, the way You want me to know You. So that I will trust You with my life and anyway that You move in my life. Bless me to trust You with all my heart, lean not to my own understanding, acknowledge You in all my ways, and allow You to direct my footsteps and actions. Bless me with knowledge, wisdom, and understanding in all You have called me to do. 
