If memory serves, Berkof stresses that the sacraments only have reference to special grace, not common grace.
Let us define our terms:
Special grace is the grace of God which he gives unconditionally to whoever he chooses to inherit eternal life (for this post we will call them “the elect,” designating that they are chosen for everlasting life in Christ). This grace is always effectual in bringing about that goal.
Common grace is any grace that can in principle be given both to someone chosen to inherit eternal life–an elect person–and to someone passed over and allowed to, ultimately, remain in their sins (for this post we will call them “the reprobate”). Common grace is not always identical to universal grace. Both the elect and the reprobate can enjoy Hawaii but not all of either group (I presume) has enjoyed that blessing of common grace. All universal grace is common grace but not all common grace is universal grace. Indeed, some forms of common grace (an Olympic gold medal for example?) may be rare common grace. “Common” here designates that it is a blessing available or given to both elect and reprobate, not that it is plentiful or universal.
With that in mind, I think we need to be careful how we restrict the sacraments to special grace. The Gospel is about special grace. When we preach the Gospel we are presenting, inviting, and challenging hearers with the grace of Jesus in his incarnation, life, death, new life, and ascension. But our words aren’t only for the elect. The reprobate here them also. They are challenged by the same message. To their eternal loss and more severe punishment, they reject the message.
In the same way, it seems to me, the sacraments are an aspect of common grace. I believe I learned this from John Murray who got it from Dr. Herman Kuiper.
The best classification with which the present writer has become acquainted is that offered by Dr. Herman Kuiper in the work aforementioned. In classifying the various manifestations of grace recognised by Calvin he gives three groups. The first category is that of the “grace which is common to all the creatures who make up this sin-cursed world…a grace which touches creatures as creatures.” This Dr. Kuiper calls universal common grace. There is, secondly, the grace recognised by Calvin as “common to all human beings in distinction from the rest of God’s creatures…a grace which pertains to men as men.” This Dr. Kuiper calls general common grace. Thirdly, there is the grace common not to all creatures and not to all men but to all “who live in the covenant sphere…to all elect and non-elect covenant members.” This Dr. Kuiper calls covenant common grace.
The “covenant sphere” would include or be identical to the visible church. In the visible church all are recipients of the preaching of the Gospel and the visible church is marked out by sacraments.
Thus, it would seem to me that we need (and do in fact) recognize the sacraments as a kind of common grace. Those to whom God gives special grace respond in faith to the promises enacted in these sacraments just as they respond to the preached Gospel.