Romans 3:24: Being justified FREELY by his GRACE through the redemption that is in Christ Jesus: NB: Freely by His Grace, hence the term Free Grace.

Grace: (χάρις/charis/grace/favour),
which in contextual etymological terms,
is the favour bestowed upon
one who does not deserved it.

Free: (ἐλεύθερος/eleutheros/free/exempt/unrestrained/not bound by an obligation).

The Gospel, believe on Christ and live.

GOSPEL

Acts 16:30b-31: Sirs, what must I do to be saved?
And they said, Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house.

I Corinthians 15:3-4: For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
And that he was buried, and that he rose again the third day according to the scriptures:

ASSURANCE

John 5:24: Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.

I John 5:13: These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.