‘By faith they passed through the Red Sea as by dry land, which the Egyptians attempting to do were swallowed up.'
Note the change from ‘he' to ‘they', made more emphatic by the fact that he could have previously said ‘they kept the Passover' rather than ‘he kept the Passover', for the Passover revealed their faith as well as his. This thus represents a specific and deliberate change in emphasis. Here all the people are seen as being drawn in and involved. Moses' part was done. Attention is now drawn to the faith of the people as a people. This ‘faith of the people' did not mean that all truly believed. It is the faith of the whole seen as one. ‘Israel' as a whole had faith, even though some within Israel did not.
Concentration is now on the faith of the many and it is contrasted with the Egyptians. Israel believed. Egypt (the representative of the world in its opposition to God) did not. Through the faith of Moses the Red Sea opened up before Israel, and through their combined faith they passed through it on dry land, while the Egyptians who lacked true faith were all swallowed up and drowned (see Exodus 14:15-31). We are to see here the faith of Moses absorbed into the resulting faith of the people in what God was doing. On being tested they did not finally return to Egypt, even though many did waver, because they held their trust in the promises of God. Their resultant increased faith is stressed in Exodus 14:31.
For not all who perished in the wilderness were unbelievers. Many were true believers, even though they were yet weak and disobedient. Indeed this is confirmed by the fact that neither Aaron nor Moses reached the promised land. Yet they were still people of faith. So it turned out that many also were disobedient believers who had to face the consequences of their disobedience and yet were not excluded from God's final mercy.