Conjunctions have sometimes a Government of Modes. Some Conjunctions require the Indicative, some the Subjunctive Mode after them: others have no influence at all on the Mode.
Hypothetical, Conditional, Concessive, and Exceptive Conjunctions seem to require properly the Subjunctive Mode after them: as, if, tho’, unless, except, whether—or, &c. but by use they often admit of the Indicative. Examples: “If thou be the Son of God.” Matt. iv. 3. “Tho’ he slay me, yet will I put my trust in him.” Job xiii. 15. “Unless he wash his flesh.” Lev. xxii. 6. “No power, except it were given from above.” John xix. 11. “Whether it were I or they, so we preach.” 1 Cor. xv. 11. The Subjunctive in these instances implies something contingent or doubtful; the Indicative would express a more absolute and determinate sense.
That expressing the motive or end has the Subjunctive Mode, with may, might, should, after it.
Lest; and that with a Negative following it; and if with but following it; necessarily require the Subjunctive Mode: Examples; “Let him that standeth, take heed, lest he fall.” 1 Cor. x. 12. “Take heed, that thou speak not to Jacob.” Gen. xxxi. 24. “If he do but touch the hills, they shall smoke.” Ps. civ. 32.[74]
Other Conjunctions, expressing a Continuation, an Addition, an Inference, &c. being of a positive and absolute nature, require the Indicative Mode; or rather leave the Mode to be determined by the other circumstances and conditions of the Sentence.
When the Qualities of different things are compared, the latter Noun is governed, not by the Conjunction than, or as, (for a Conjunction has no Government of Cases,) but by the Verb or the Preposition, expressed, or understood. As, “Thou art wiser than I [am.]” “You are not so tall as I [am.]” “You think him handsomer than [you think] me; and you love him more than [you love] me.” In all other instances, if you complete the Sentence in like manner, by supplying the part which is understood, the Case of the latter Noun will be determined. Thus, “Plato observes, that God geometrizes; and the same thing was observed before by a wiser man than he:” that is, than he was. “It was well expressed by Plato; but more elegantly by Solomon than him:” that is, than by him[75].
The Conjunction that is often omitted and understood: as, “I beg you would come to me:” “See, thou do it not:” that is, “that you would;” “that thou do[76].”
The Nominative Case following the Auxiliary, or the Verb itself, sometimes supplies the place of the Conjunctions if and tho’: as, “Had he done this, he had escaped:” “Charm he never so[77] wisely:” that is, “if he had done this;” “tho’ he charm.”