Alma had already asserted (v. 8) that the records had effectively brought people to the Messiah. He cites as an example the successful mission of Mosiah’s sons to the Lamanites. In verse 10 Alma extrapolates from that success to a promising future in which “many thousands” more Lamanites and “our stiffnecked brethren, the Nephites” may yet be converted. He projects the past use of the records to convert Lamanites into the future of continued conversions. Alma understands that major changes are afoot. He is here presaging the approaching war.