The Kingship of Christ and the Baptism and Discipleship of the Nations.
"All power is given unto me in heaven and in earth. Go ye therefore and 'make all nations disciples', baptising them ... teaching them to observe all things whatsoever I have commanded you ..." [Matth. 28:18-20].
"God ... commandeth all men every where to repent"[Acts 17:30]. We have been commissioned by He who has all power to 'make all nations disciples', the aorist imperative active indicates that this is speaking of a point in time when discipleship begins and that the Church is the active instrument. This is important in understanding the Great Commission, men are called to discipleship and the first act of obedience is baptism followed by teaching them to observe all things Christ has commanded.
As infants are part of the nations to be discipled they are included. However the Church obviously requires the consent and co-operation of their parents or guardians to be successful. Christian parents are clearly commanded to disciple their children, the first act of which is submission to baptism. So the baptism of infants is a parental duty as part of bringing them up in "nurture and admonition of the Lord" [Eph. 6:4] and flows from the all embracing nature of the Great Commission.
The promise of Psalm 67 is that "God shall bless us and all the ends of the earth shall fear Him", every knee is destined to bow to King Jesus [Isa. 45:23, Rom. 14:11, Phil. 2:10], his Kingdom will destroy and displace Daniel's fourth Kingdom and cover the whole world [cf. Dan. ch. 2 & 7].
If this is to be so then it means that we will baptise the unregenerate, the false professor, the hypocrite, but from the beginning the Church baptised all who according to age and circumstances appeared to be disciples of Christ.
Yes the Church will make mistakes by this policy, Simon was baptised [Acts 8:13] and his true state discovered later on. While Church discipline demands separation from false teachers and outward conformance to Christian standards, the parables of the Drag-net, the Wheat and Tares, the Sower all speak of false professors being in the Kingdom, a Kingdom which will cover the whole world as the parable of the mustard seed shows [Matth. ch. 13, Mk ch. 4 and Lk ch. 8 & ch. 13].
On a deeper level it is quite clear from Romans, Galations, and Hebrews that while the Christian Covenant sets aside the Mosaic Covenant it preserves and enhances the Abrahamic Covenant which included the believer's seed. The promise of the New Covenant, the promise of the Spirit, of which water baptism is both the sign and seal of the is the inheritance of all those within the Abrahamic Covenant [Acts 2:39].
Hence Paul was astonished that the disciples of John had neither heard of, nor received the Spirit despite having been baptised to believe on "him which should come after [John], that is on Christ Jesus. When they heard they were baptised in the name of the Lord Jesus and when Paul had laid his hands on them the Holy Ghost came upon them" [Acts 19:4-6 cf. Herman Hoeksema, Reformed Dogmatics, 1966, p671.].
The exception is those converted from without the Abrahamic Covenant, in some cases they receive the Spirit before baptism and so receive the seal afterwards [Acts 10:47].
Abraham believed and was circumcised but then he also circumcised his children who had been brought within the Covenant. The only discussion in the early Church over the parallel between baptism and circumcision was over delaying baptism until the eighth day or not, not whether infants ought to be baptised.
While a correct ecclesiology will not bring revival, the plethora of opinions over this and other issues among Evangelicals does suggest we have grieved the Spirit, lack wisdom and hence the general lack blessing.