“What was circumcision for? Reference Genesis 17:12-14.”
Circumcision was the right that marked the person as an Israelite - which status he had at birth. It marked them as members of the Old Covenant.
Water baptism is the rite of passage that marks one as born again in Christ, and it happens after the second birth. It marks us as under the New Covenant.
Unlike birth into Israel, no infant has experienced the second birth required for entering the Kingdom of Heaven. We baptize infant Christians, but we do not baptize non-christian infants, so to speak. One cannot become an “infant Christian” without believing.
Infant baptism is like trying to circumcise someone who is still in the womb.
Just as physical birth is required for circumcision, spiritual birth is required for water baptism.
“Do you make decisions for your children until they reach the age of reason?”
Yes, where possible. I cannot decide for them to repent and believe, which is the requirement to become a believer...
I’ll add this: If I could make the decision for others to enter the Kingdom of Heaven, I would do so for ALL. But no one can make that decision for another. I cannot repent and believe on behalf of my wife, nor can I do so for an infant anywhere.
I can, as head of the household, decide my house will be run on the principles of God. In that sense, I CAN save my entire household - in the sense of sanctification (separation from the world):
“If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. Otherwise your children would be unclean, but as it is, they are holy.”
But that talks of sanctification, not justification - and it may well be the context that talks about an entire household being “saved”. Justification is required for someone to become a citizen of Heaven, to board the SS Jesus and take a cruise whose destination is to be conformed to the likeness of Christ. But you can be made different (separate / holy) by the decision of another to have his home abide by different principles.
As noted in Acts 16:
“And he rejoiced along with his entire household that he had believed in God.”
His household rejoiced that he had believed...
So too would baptism mark infants as members of the New Covenant under to covering of parents as it was with the Israelites under the Old Covenant.
>>Yes, where possible. I cannot decide for them to repent and believe, which is the requirement to become a believer...<<
Children are under the covering of the believing parents until the age of reason. Just as children in Israel were dedicated to God as infants so too children of believers.
The legalistic view of baptism is a dangerous thing.