https://www.mljtrust.org/sermons-online/john-1-12-13/a-more-excellent-sacrifice/

The Christian is meant to know that they are the child of God. Dr. Martyn Lloyd-Jones elaborates that there are two types of assurance: the test of faith and the test of the Christian walk. In this sermon on John 1:12–13 and Hebrews 11 called “A More Excellent Sacrifice,” Dr. Lloyd-Jones examines both tests in regard to the example of Cain and Abel. He describes how Cain and Abel relied on two separate sources for authority. While Cain relied on his own merit and reasoning, Abel offered a more excellent sacrifice and relied on faith. This is still true of humanity today. There are two sources of authority in the world: reliance on deeds, rationale, or penitence to appease the wrath of the almighty God or relying by faith on the sacrifice of Christ to appease God and present the Christian as righteous. The Christian can ask themselves if they, by faith, submit themselves to the holy Scriptures, and are perceived by the world to rely on Scripture and are accused of taking religion too seriously. These are very likely signs that the Christian relies on Christ as their Savior and Lord.