Knowing God's will, as Romans 12:2 presents it, is inseparable from refusing to conform to the world and renewing the mind; the three are one process, and proving God's good, acceptable, and perfect will happens as believers put off the old man and put on Christ. Scripture is the starting point, since its 31,000-plus verses declare God's will, as in the Ten Commandments, the Beatitudes, and the fruit of the Spirit. God's Spirit helps believers understand it, which the carnal man cannot do. Yet learning and accepting these declarations is only a child's first step. The Greek dokimazo means to test, examine, and prove genuineness, as gold is tried by fire in I Peter 1. God tests the genuineness of faith, and He expects believers to test His way by living it, as in the invitation to prove Him through tithing in Malachi. I Thessalonians 5:21, I John 4:1, Ephesians 5, and Philippians 1 teach the same. Such proving is often slow and requires deep thought and discernment, not snap judgments, especially in relationships. It calls for alertness and urgency, since time is short. Abraham is the model: he obeyed God's command to leave for Canaan, endured trials, and learned through both failure and success, climaxing in the offering of Isaac. By acting on what God says and seeing His response, believers come to know experientially that His will is right, and it becomes engraved in character and produces righteous fruit that glorifies God.

We can know God's will in any situation by knowing His character, because He acts out of it. Ephesians 5:15-17 calls believers to walk wisely and understand the Lord's will, but the Bible rarely supplies a verse or example that matches every circumstance. Principle must then be applied, and a Christian of many years should not have to cry out for intervention every time. Children copy their parents, so those called out of darkness as children of light imitate God and Christ (John 8:37-44; I John 2:6; I Peter 2:21; John 13:15; I Corinthians 11:1). Jeremiah 31:33-34 shows that God intends His people to know Him intimately, with His law in their minds and hearts. Knowing a trait means understanding how it works and applies in practice, such as how justice and mercy balance. Holiness is the foundation of all God's traits, meaning separation, consecration, and excellence, and it is moral purity rather than ritual (Mark 7). Knowing it does not always give a specific course of action but eliminates immoral options and points the right direction. David eating the showbread (Matthew 12) shows how understanding God's holiness and mercy let him weigh preserving life above ritual law. Obedience to God's commands also brings understanding over time (Ephesians 5:10; Psalm 111:10), as an act of faith.

God's will is what He wants to occur, both in His overarching purpose and in individual lives. Since humans made in His image have personal wills, God does too, and as Supreme Being His will prevails. It is good, acceptable, and perfect, and Christians are transformed from carnal to godly minds by discerning it and conforming to it. Jesus says that whoever wills to do God's will shall know whether His doctrine is from God (John 7:17). God's will is known through revelation, which He has gathered in the sixty-six canonical books of the Bible. Isaiah 8:16 and Paul's "whole counsel of God" (Acts 20:27) indicate that this testimony is bound and sealed, which precludes any new revelation and means Scripture contains all that is needed for salvation. Understanding it, however, requires God's Holy Spirit, since "no one knows the things of God except the Spirit of God" (I Corinthians 2:11). Without the Spirit, received through the laying on of hands, Scripture remains veiled in mystery. With it, a person can have the mind of Christ, and Jesus told His disciples that the mysteries of the kingdom had been given to them. This gift obligates God's people to seek His will in everything and practice it with understanding and diligence, imitating the prompt obedience of angels until all humanity eventually submits to God.

Knowing God and being assured of eternal life is the essence of His will for believers. God's will is that we believe in His Son, receive the good news, rejoice in Christ's commands, and love others in deed and truth, so that we know that we know the Father through Jesus Christ. Based on I John 2:3-6, this knowing is personal and intimate, not mere information about Christ, and it includes awareness of being in Christ, like a branch in the vine. The test is ethical rather than mystical: those who keep His commandments and walk as Christ walked show they know Him. Obedience does not justify, since justification comes by faith, but it evidences new birth. Experiences, feelings, and visions are not the measure, and any approach that bypasses Christ, as Gnostic mysticism does, is not Christian. Knowing God's love comes through Christ, who reveals the Father. Ten practical tests confirm it: losing the sense that God is against us while retaining reverent awe, sensing that He loves us and works all things for good according to His eternal purpose (prothesis), a sense of forgiven sins and gratitude, growing revulsion of sin, a desire to please Him, a longing for closer intimacy, regret that our love is so poor, and joy in hearing about the Father and Christ. Doubt dishonors God, so this assurance must be held in faith, particularly when approaching Passover.