As the host of heaven cannot be numbered, neither the sand of
the sea measured
As the stars of heaven are innumerable, and the sand of the sea immeasurable: so will I multiply the seed of David my servant;
the Messiah; the son and antitype of David; and who is often called by his name; and as the son of David is the servant of the Lord, his spiritual seed are meant, which shall endure for ever; and in Gospel times, especially in the latter part of them, shall be very numerous; see ( Psalms 89:29 Psalms 89:36 ) ; and the Levites that minister unto me;
meaning the same as before; not ministers of the Gospel, for they never were, or will be, so numerous as here expressed; but true believers in Christ, who are all priests unto God, and minister in holy things, offering up the spiritual sacrifices of prayer and praise through Christ: these Levites are the same with the seed of David, or Christ, in whom the kingdom and the priesthood are united.
The Brenton translation of the Septuagint is in the public domain.