If babies and infants were permitted to be baptised unto salvation then scriptures would openly teach this.
Jesus and the apostles teach us in scripture to repent and to be baptised (full immersion not sprinkled) and to confess our faith - babies and infants cannot do this nor need to - it is to do with an age of understanding.
1Corinthians 7:
12 To the rest I say, not the Lord, that if any brother has a wife who is an unbeliever, and she consents to live with him, he should not divorce her. 13 If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. 14 For the unbelieving husband is consecrated through his wife, and the unbelieving wife is consecrated through her husband. Otherwise, your children would be unclean, but as it is they are holy.