A summary of Thomas Blake argument showing that the Anti-paedobaptist John Tombes cannot account for the hope of the salvation of infants:

1. Tombes has no Scripture supporting the hope of salvation of infants. The only one is Rom 9 but that is not to the point.

God has revealed the way of salvation, and we don't look to the secret will of God, but to his revealed will. We learn not to carry our hopes beyond his promise.

If we can carry the hope of salvation beyond the limits of God’s promise then any may be saved, it is all arbitrary.

Therefore, to deprive infants of all promises, you deprive them of all hope of salvation.

2. Our divines teach that the invisible Church is (in God’s ordinary dispensation) within the visible.

'Out of the church there is no salvation' is not to be so rigidly understood that all not actually admitted but according to the Apostles words, all aliens and strangers from it, as without any right of relation to it, are excluded.

Therefore, there can be no expectation of the salvation of infants by those who confess their original corruption and deny them all title to the Church and right to baptism.

Similarly, John Owen wrote:

"If, therefore, God denies the sign unto the infant seed of believers, it must be because he denies them the grace of it..."

See the last quote in this post: https://www.reformation21.org/blog/parental-comfort