Now, below, Peter’s example to us in Scriptures arranged within the framework of Eph 5:8.

1. FOR YOU WERE FORMERLY DARKNESS: Our life before Christ, i.e., 'Who You Were'

                       Peter, like all people, was a lost sinner before he met Jesus.

 2. BUT NOW YOU ARE LIGHT IN THE LORD: Our life as a Child of God, i.e., 'Who You Are'

                       Peter was born again when he believed in Jesus. He instantaneously and irreversibly became a Child of God.

            1. This beginning of His signs Jesus did in Cana of Galilee, and manifested His glory, and [Peter] believed in Him. (Saved!!!; John 2:11

           Jesus secured Peter's place in Heaven. Jesus intervenes, intercedes, and advocates for us after we are saved so that He "shall lose none" of His children. Take special notice of the following underlined-verses which show Peter's guaranteed salvation BEFORE some of his most grievous sins occurred, as noted further below.

            2. And Jesus said to them, "Truly I say to you, that you who have followed Me, in the regeneration when the Son of Man will sit on His glorious throne, you [Peter and the Apostles] also shall sit upon twelve thrones, judging the twelve tribes of Israel. (Matthew 19:28

            3. that you [Peter and the Apostles] may eat and drink at My table in My kingdom..."Simon [Peter], behold, Satan has demanded permission to sift you like wheat; but I have prayed for you, that your faith may not fail; and you, when once you have turned again, strengthen your brothers." ( Note that Peter is guaranteed his place in Heaven, and that Jesus will pray—and thus guarantee—that his faith will never fail; Luke 22:30-32)

            4. Simon Peter said to Him, "Lord, where are You going?" Jesus answered, "Where I go, you cannot follow Me now; but you shall follow later." ( Another guarantee of Peter’s place with the Lord in Heaven, John 13:36)

            5. "Father, I desire that they also, whom Thou hast given Me, be with Me where I am [in Heaven], in order that they may behold My glory, which Thou hast given Me; for Thou didst love Me before the foundation of the world. (John 17:24

3a. WALK AS CHILDREN OF LIGHT:

Our walk as a Child of God, i.e., Walk like 'Who You Are', not like 'Who You Were' (“the spirit is willing [but unable because the “flesh is weak”]..." Mat 26:41;

Therefore, “walk by the [Holy] Spirit, and you will not carry out the desire of the flesh…”, Gal 5:16; "A good tree [the Holy Spirit in us] cannot produce bad fruit... Mat 7:18)

When Peter — his spirit willing, but his flesh weak — walked by the Holy Spirit which he received AT THE MOMENT he was saved, though still failing “in the flesh”, he walked the righteous walk of the Holy Spirit of God the Father and God the Son.

            6. ...for He who effectually worked for Peter in his apostleship to the circumcised effectually worked for me also to the Gentiles. (Paul’s testimony of the Holy Spirit working within Peter, enabling him to ‘Walk Like Who You Are’—a Child of God; Galatians 2:8

He said to them, "But who do you say that I am?"

And Simon Peter answered and said, "Thou art the Christ, the Son of the living God."

And Jesus answered and said to him, "Blessed are you, Simon Barjona, because flesh and blood did not reveal this to you, but My Father who is in heaven.                 (Here Peter, a born-again Child of God, is moved by God to make this great confession; Matthew 16:15-17

            7. Then Peter, filled with the Holy Spirit, said to them, "Rulers and elders of the people, “... there is salvation in no one else; for there is no other name under heaven that has been given among men, by which we must be saved." (Peter’s witness to Jesus; Acts 4:8-12

            8. And on the next day, as they were on their way, and approaching the city, Peter went up on the housetop about the sixth hour to pray (Peter prayed to the Lord in Heaven who he had once walked with on earth... and then believed in for salvation; Acts 10:9

            9. And after there had been much debate, Peter stood up and said to them, "Brethren, you know that in the early days God made a choice among you, that by my mouth the Gentiles should hear the word of the gospel and believe.

"And God, who knows the heart, bore witness to them, giving them the Holy Spirit, just as He also did to us;

and He made no distinction between us and them, cleansing their hearts by faith.

"Now therefore why do you put God to the test by placing upon the neck of the disciples a yoke which neither our fathers nor we have been able to bear?

"But we believe that we are saved through the grace of the Lord Jesus, in the same way as they also are." (Acts 15:7-11; Peter later sinned in his witness to this same Gospel, note #18 below)

[ 3b.-implied- DON'T WALK AS CHILDREN OF DARKNESS ] ( "... but the flesh is weak." (Mat 26:41; “...walk by the Spirit, and you will not carry out the desire of the flesh”...Gal 5:16;  "... nor can a bad tree [the flesh] produce good fruit.” Mat 7:18)

Jesus was well aware of our challenge, as a born-again Child of God, when He encouraged us to,

"Keep watching and praying, that you may not enter into temptation; the spirit is willing, but the flesh is weak." (Matthew 26:41

When Peter — his spirit willing, but his flesh weak — walked by his fleshly impulses which had ruled him BEFORE he was saved, he walked his former walk of darkness in sin. But Peter's place in Heaven was secured AT THE INSTANT of his Faith in Christ (#1above), and confirmed by the promises (which are also prophecies, given by Christ  in #2-5 above) which were given BEFORE several of the sins of Peter (#10-18 below).

For example, Peter's place in Heaven was guaranteed in Matthew 19:28 BEFORE his sin of Matthew 26:74.

            10. And an argument arose among them [Peter, Apostles] as to which of them might be the greatest. (Luke 9:46

            11. And there arose also a dispute among them [Peter, Apostles] as to which one of them was regarded to be greatest. (Luke 22:24

            12. And Peter took [Jesus] aside and began to rebuke Him, saying, "God forbid it, Lord! This shall never happen to You." (Mat 16:22

            13. And He came to the disciples and found them sleeping, and said to Peter, "So, you men could not keep watch with Me for one hour? (Mat 26:40

            14. Then he [Peter] began to curse and swear, "I do not know the man [Jesus]!" And immediately a cock crowed. (Mat 26:74

            15. And they said, "Lord, look, here are two swords." And He said to them, "It is enough." (Luke 22:38

            16. And when those who were around Him saw what was going to happen, they said, "Lord, shall we strike with the sword?"

And a certain one of them [Peter] struck the slave of the high priest and cut off his right ear.

But Jesus answered and said, "Stop! No more of this." And He touched his ear and healed him. (Luke 22:49-51

            17. Peter therefore seeing him said to Jesus, "Lord, and what about this man?" (John 21:21

            18. But when Cephas [Peter] came to Antioch, I opposed him to his face, because he stood condemned...

And the rest of the Jews joined him [Peter] in hypocrisy...they were not straightforward about the truth of the gospel, (Gal 2:11-14

How were Lot, Samson, and Solomon, each with many failures like Peter, saved? HERE...