How do we know that justification is by grace alone?

The doctrine of justification by grace alone is rooted in the Scriptures, particularly seen in Romans 3:24, where Paul asserts that we are justified freely by God's grace. This means that no human action or merit can contribute to our justification; it is solely the work of God. Romans 8:33 further stresses that it is God who justifies, emphasizing His sovereign authority in declaring sinners righteous. Faith is involved, yet it is a gift from God, not a work of man, as Ephesians 2:8-9 clarifies that faith itself is not of ourselves but entirely of God's grace. Thus, justification stands as a testament to the unmerited favor bestowed upon the elect.