Acts 5:39

but if it be of God The verb is not in the same mood as in the previous clause, and had the construction been in classical Greek, it might have indicated some opinion on Gamaliel's part of the truth of Christianity = "If it is [as it is] of God." But in the N. T. the construction indicates no more than a simple conditional. Yet to mark the difference of phrase, read here, But if it is of God.

ye cannot overthrow it The best authorities read, ye will not be able to overthrow it.

lest haply ye be found, &c. The clause depends on, "Take heed to yourselves …" (Acts 5:35).