The Sacrament of confession is Biblical.
Here is just ONE of the prefigurements from the Old Testament to confession in the New Testament the way that Jesus FULFILLED it and not abolished it.
Num 5:5-7 wrote:5 The LORD said to Moses,
6 "Tell the Israelites: If a man (or a woman) commits
a fault against his fellow man and wrongs him, thus breaking
faith with the LORD,
7 he shall confess the wrong he has done, restore his
ill-gotten goods in full, and in addition give one fifth of
their value to the one he has wronged.
Here is another one; both are from the same book & chapter. This is a prefigurement of confession and the offering for atonement is a prefigurement of the penance that is given once I confess my sins. The penance is not for the forgiveness of my sin because God has already forgiven me, but rather it is for the temporal punishment due to sin. The Catholic church did not make that up as mere humans in an institution. Jesus fulfilled the law in the New Testament and HE established it in His Church as He gave the power to forgive sins to His Apostles.
Lev 5:5-6 wrote: 5 then whoever is guilty in any of these cases shall
confess the sin he has incurred,
6 and as his sin offering for the sin he has committed he
shall bring to the LORD a female animal from the flock, a ewe
lamb or a she-goat. The priest shall then make atonement for
his sin.
Lev 5:8 wrote: 8 He shall bring them to the priest, who shall offer the
one for the sin offering first. Snapping its head loose at the
neck, yet without breaking it off completely,...
Now here is biblical evidence of the Sacrament of Confession from the New Testament. Please don't make more of the verses than what is clearly stated. A lot of people make that mistake. It is not more than what it is. It's just very simply stated;
John 20:21-23 wrote:21 (Jesus) said to them again, "Peace be with you. As
the Father has sent me, so I send you."
22 And when he had said this, he breathed on them and
said to them, "Receive the holy Spirit.
23 Whose sins you forgive are forgiven them, and whose
sins you retain are retained."
Here is biblical evidence of the Sacrament of anointing of the sick;
Jas 5:14-15 wrote:14 Is anyone among you sick? He should summon the
presbyters of the church, and they should pray over him and
anoint (him) with oil in the name of the Lord,
15 and the prayer of faith will save the sick person, and
the Lord will raise him up. If he has committed any sins, he
will be forgiven.