THAT is the point.
It is not a biblical practice.
1Cr 6:11 And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
Hbr 4:16 Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.
Tts 2:14 Who gave himself for us, that he might redeem us from all iniquity, and purify unto himself
Rom 3:24 Being justified freely by his grace through the redemption that is in Christ Jesus: a peculiar people, zealous of good works.
The confessional "box" is not biblical; the practice is. Jesus granted the Apostles His authority to forgive sins.
In John 20:23 - Jesus says, "If you forgive the sins of any, they are forgiven. If you retain the sins of any, they are retained." In order for the apostles to exercise this gift of forgiving sins, the penitents must orally confess their sins to them because the apostles are not mind readers. The text makes this very clear.
In James 5:16 - James clearly teaches us that we must “confess our sins to one another,” not just privately to God. James 5:16 must be read in the context of James 5:14-15, which is referring to the healing power (both physical and spiritual) of the priests of the Church. Hence, when James says “therefore” in verse 16, he must be referring to the men he was writing about in verses 14 and 15 – these men are the ordained priests of the Church, to whom we must confess our sins.
So did the first Christians practice the Sacrament of Confession? We know from The Early Church Fathers that they did.
“In church confess your sins, and do not come to your prayer with a guilt conscience. Such is the Way of Life...On the Lord's own day, assemble in common to break bread and offer thanks; but first confess your sins, so that your sacrifice may be pure." Didache, 4:14,14:1 (c. A.D. 90).
"Father who knowest the hearts of all grant upon this Thy servant whom Thou hast chosen for the episcopate to feed Thy holy flock and serve as Thine high priest, that he may minister blamelessly by night and day, that he may unceasingly behold and appropriate Thy countenance and offer to Thee the gifts of Thy holy Church. And that by the high priestly Spirit he may have authority to forgive sins..." Hippolytus, Apostolic Tradition, 3 (A.D. 215)