Gennadius of Constantinople

The cloud was a figure standing for the grace of the Spirit. For just as the cloud covered the Israelites and protected them from the Egyptians, so the Spirit’s grace shields us from the wiles of the devil. Likewise, just as the crossing of the sea protected them from their enemies and gave them real freedom, so baptism protects us from our enemies. That was how the Israelites came to live under the law of Moses. This is how we, in baptism, are clothed with the Spirit of adoption and inherit the covenants and confessions made in accordance with the commands of Christ.

By faith, Paul does not mean the common and universal faith of believers but the spiritual gift of faith. The two things have the same name, because when the Holy Spirit comes upon us it is our human faith which expands to make room for the divine gift.