A time when a sinner first experiences salvation!
Baptism, where you submit yourself to the will of God and he bestows upon you the gift of salvation. Buried with Christ IN Baptism, IN WHICH you are also raised with him THROUGH FAITH for a new life.

In him you were also circumcised with a circumcision not performed by human hands. Your sinful nature was put off when you were circumcised by Christ, having been buried with him in baptism, in which you were also raised with him through your faith in the working of God, who raised him from the dead. When you were dead in your sins and in the uncircumcision of your sinful nature, God made you alive with Christ. He forgave us all our sins,
Colossians 2:11-13 TNIV

In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ, buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead. And you, being dead in your trespasses and the uncircumcision of your flesh, He has made alive together with Him, having forgiven you all trespasses,
Colossians 2:11-13 NKJV

Colossians 2:12
(ESV)  having been buried with him in baptism, in which you were also raised with him through faith in the powerful working of God, who raised him from the dead.
(KJV)  Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
(NASB)  having been buried with Him in baptism, in which you were also raised up with Him through faith in the working of God, who raised Him from the dead.
(NIV)  having been buried with him in baptism, in which you were also raised with him through your faith in the working of God, who raised him from the dead.
(NKJV)  buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead.

Treasury of Scripture Knowledge
Colossians 2:12
Buried: Romans 6:4-5
baptism: Romans 6:3; 1 Corinthians 12:13; Gal 3:27; Eph 4:5; Tit 3:5-6; Heb 6:2; 1 Peter 3:21
wherein: Col 3:1-2; Rom  6:8-11, Rom 7:4; 1 Cor 15:20; Eph 1:20, Eph 2:4-6, Eph 5:14; 1 Peter 4:1-3
the faith: Luke 17:5 : John 1:12-13, John 3:3-7; Acts 14:27; Eph 1:19, Eph 2:8, Eph 3:7, Eph 3:17; Philippians 1:29; Heb 12:2; James 1:16-17
who: Acts 2:24; Romans 4:24; Heb 13:20-21