There's this meme:
"Don't confess your sins to a man in a box. He cannot forgive you. Only God can forgive sins. Not man. Read your Bible."
How should a Catholic respond?
We should say: we agree with you that "only God can forgive sins". (And that you should read your Bible.) 100% agree.
In fact, our Catechism says just that:
"Only God forgives sins"--CCC 1441
HOWEVER, we also understand that God has given authority to Christ, and Christ to His Church, to forgive sins...in HIS name.
"Since he is the Son of God, Jesus says of himself, "The Son of man has authority on earth to forgive sins" and exercises this divine power: "Your sins are forgiven." Further, by virtue of his divine authority he gives this power to men to exercise in his name."--CCC 1441
Catholic Apologist Trent Horn presents an apologia (defense) of sacramental confession to a priest with this parallel: many Protestants believe in baptismal regeneration--that is, they believe (like Catholics) that baptism really does indeed wash away our sins. To these Baptism-Does-Remove-Our-Sins Protestants, we can tell them, "Just like you understand that it's not the minister that's washing away the sins--it's God, acting through the minister--when he's baptizing someone...so, too, is it not the priest that's forgiving our sins in confession--it's God, acting through the priest."
There are some Protestants, however, who think that baptism doesn't really do anything...it's just an outward sign of one's belief in Christ, and it does NOT wash away our sins (which is, ironically, contrary to Scripture which states it DOES wash away our sins: "Now, why delay? Get up and have yourself baptized and your sins washed away, calling upon his name.--Acts 22:16
To these Protestants who don't believe in baptismal regeneration...we can ask them who they ask to forgive their sins. Their answer, of course, will be: Jesus!
To which we can ask: where does the Bible say to confess our sins to the Risen Jesus?
In fact, the Bible says we should confess our sins to one another.
Therefore, confess your sins to one another and pray for one another, that you may be healed. The fervent prayer of a righteous person is very powerful.--James 5:16
And, the Bible shows that authority was given to the apostles to forgive sins.
And when he had said this, he breathed on them and said to them, “Receive the holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained."--John 20:22
Truly, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.--Matt
So, if one reads his Bible, we can see that it's actually Catholicism which is more biblical than those Bible-Christian churches which reject "confessing to a man in a box."