Jesus and the Holy Spirit start the intercession process by the command of God the Father. They both pray for us, and the Holy Spirit comforts us and equips us to respond well. We can respond with all our emotions, and He trains us to conform to Jesus' intentions and reactions. He advocates for our benefit.
Satan is the Adversary: that is his name. But, we must not think that he is adversarial chiefly against us. His sin, like ours, is against God. When he goes before God, he accuses the saints. His words may be right, but not good or helpful. He did this to Job, saying that he would sin against the Lord- and he was right (Job 1:9-12). He doesn't do it to build us up, but to make us unfruitful and thereby disrupt the Church giving God the glory He is due.
We can either be advocates or adversaries. We can be someone's personal Satan by either being apathetic and not telling them what they need to hear. Or communicating with them things that distract from God's glory. Like reminding them of past faults, as if God's grace isn't sufficient to move them away from sins and mistakes. Not forgiving those who've repented. Describing their problems with worldly adjectives instead of calling problems what they are- like calling people "toxic" instead of sinful. This obscures the prescription through wrong description, and makes reconciliation that much harder. God will move against such adversaries, and will not forgive their day to day sins (Matt. 6:14-15).
We advocate for others when we place ourselves in a position to understand their viewpoint, rather than to just be heard. To fully know the matter before speaking on it (Prov. 18:13). We won't pray for them effectively if we're chiefly concerned with our own opinion. We will come to shame if we speak into a matter before we wrap our heads around what the person is truly going through. So we must ask them and ask for God's viewpoint to be made known.
There is an element of being understood in prayer, however. Paul writes that those who aren't understood while speaking in tongues should hold their peace in the Church (1 Cor. 14:28). That when we pray, the good words coming from our lips aren't just going to God- there are people listening who can say "Amen" at our giving of thanks (1 Cor. 14:16-18).
We use our words to counsel and speak truth over others. Whatever could not be said to the other in discussion can be said openly in prayer. Whether it's a subtle rebuke about the nature of their sin or encouragement that God's work is being done in their life. Rebukes should be used sparingly, however. Pray with others often in person, and pray out loud for them as soon as an opportunity presents itself. Not only does this edify them with our words, but it makes sure we are setting them as a priority, instead of forgetting to pray later on in private.
We should reiterate what they've said, in specifics. If we pray for generic things, we'll get generic answers. This shows that we've grasped what they're dealing with, and have diligently considered them. But it also is an opportunity to put it in a new context by saying it in a different way. If they've said it in a hopeless manner, we can bring God's good will into view. If they've said it in an angry or emotionally charged way, we can say it with soberness. Paul says that the hope of glorification God provided for us should lead us to speak about God's will in plain terms (2 Cor. 3:12). We can also give hope by expounding on something through making a reference to what someone else did in Scripture, and how God was faithful in it.
Rejoice with those who rejoice (Rom. 12:15). We want to elevate God's Word and the Church. So if our friends are rejoicing, even if it's slightly off in doctrine, we want to meet them with similar praises to God. This may give opportunity to expound on the truth if they know we're in it with them, not being naysayers. However, if it can be overlooked, overlook it. God is all knowing and all powerful. We know that He demonstrates self control in not correcting us every time we may say something a little off.
Weep with those who weep. Do not be minded towards lofty things, but come down to those of low estate (Rom. 12:16). Those whose minds are sad or despondent, we praise God that we're with them. But we do not praise in order to override their sadness. Don't be like Job's friends (Job 6:25-27). Such a thing is obnoxious. Do not sing happy songs to heavy hearts, like you wouldn't take away their coat in cold weather (Prov. 25:20). Weep with them, and move your innermost being towards them. This mourning will give them a heart of wisdom (Psalm 90:12). As sorrow is better than laughter, so wise men linger on the sad truths (Ecc. 7:3-6).
While we want good things for others, we do not linger on circumstances. We emphasize sanctification. Like in counseling, we want the feelings of another and their circumstances to get more pleasant, but it's not the goal for this life. The truth is that we all experience death from day to day. And we will die. But death's sting has been taken away. We know God's will, and it's not just that other pleasant opportunities "may" come along. But emphasizing sanctification means that we linger on the transformation to Christ's likeness.
For which cause we faint not; but though our outward man is perishing, the inward man is renewed day by day. For our light affliction, which is but for a moment, works for us a far more exceeding and eternal weight of glory; While we look not on the things which are seen, but on the things which are not seen: for the things which are seen are temporal, but the things which are not seen are eternal (2 Cor 4:16-18).
Pray for our leaders, and for all who are in authority (1 Tim. 2:1-4). Give thanks for them. Ask them how they are and how we can pray specifically for them. Serve and support them well. Do this not only for those you enjoy, but also for the unruly (1 Peter 2:18). Jesus wants to save them, just as He saved us.
Do not stop at prayer. If we know that someone has a need, and we are in a position to help- whether it be monetary, food, shelter, labor, or a connection that we have that could fulfill that need- it is our obligation to do so. Only praying for their needs and leaving in this case is of no profit, because God sends us to be answers to prayer (James 2:15-16). Come to the end of what God has empowered us to do, and rest in His grace for you and gracious timing for them.
We must be mindful of our own need for prayer as well. Jesus tells us to look at our own sins as more significant than another's (Matt. 7:3-5). Paul demonstrated this godly shame (1 Tim. 1:15-16). He asked for prayer so that he could keep on going, speaking the Word with boldness (Eph. 6:19-20, 2 Thess. 3:1-2). We can serve an idol of helping when we linger too much on our desire to help others, as if we had what they need in ourselves. As if God's wisdom originated in us.
We need to ask for help, and be desperate for God's work. Long for the fellowship of the Church. Those who do not gather with the Church are in Satan's domain, and can have their hearts hardened by the deceitfulness of sin (Heb. 3:12-13). The text says that this communication should be happening daily. We should be confessing and repenting alongside those in the Church. We confess specifics, and when those who are dedicated to the Lord pray for us strategically, it edifies us and the communication with God is powerful (James 5:16). Jesus is in the midst of those gathered in His name, and He will respond in favor (Matt. 18:19-20).
Jesus is our Mediator, and High Priest. The only one. There aren't other saints in heaven interceding for us- there's no such thing in Scripture. Such things as praying to the dead or for the dead belong to those with familiar spirits or necromancers. Not God's people. Even if one can be communicated with, they do not want to be (1 Samuel 28:8-19). Jesus' mediation, Himself being God, is sufficient. He calls the living to stand in the gap and advocate for others as priests, alongside Him- because without Him there would be none (Ezek. 22:30, Psalm 106:23, Is. 59:16).
And the very God of peace sanctify you fully; and I pray God- your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
Faithful is he that calls you, who also will do it.
1 Thessalonians 5:23-24