What is the meaning of Romans 5:1?

1 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ: (Romans 5:1 KJV)

William Burkitt’s Commentary

The first blessed effect and sweet fruit of our justification by faith is peace and reconciliation with God. Pardon and peace go together, and accompany one another; a sinner being discharged from guilt and thereby from his obnoxiousness to God’s wrath is instantly brought into a state of friendship and reconciliation with God; for there is no middle state between his favour and his wrath.

Learn hence, 1. That peace is proclaimed in heaven between God and every justified person whatsoever, the enmity between God and such a soul being taken away: Peace, I say, is proclaimed in the sinner’s conscience: A person may be in a state of peace and yet want the sense of peace.

Again, There is a twofold peace with God; one which is opposite to God’s paternal anger as a father. Now, the apostle here speaks of the former.  Being justified by faith, we have peace with God; that is, God has no more hostile enmity against us and will not satisfy his justice upon us by punishing us; but if we offend him, we shall certainly fall under his frowns and chastisements and feel the effects of his heavy displeasure as an angry father!

With this agrees that of the learned and pious Bishop Davenant:  Deus absolvit justificatum ab omni pana satisfactoria, sed non ab omni pana medicinali & castigatoria.

Learn, 2. That our reconciliation with God is settled upon a sure foundation by Jesus Christ;  We have peace with God through our Lord Jesus; that is, through him as a Mediator between God and us; he made peace by the blood of his cross, Col 1:20, that is, by his blood shed upon the cross; he meritorious satisfaction brought us into a state of peace and reconciliation and his prevailing intercession keeps us in it:  Being justified by faith, we have peace with God through our Lord Jesus Christ.