**EXPOSITION OF THE MORAL LAW.**
A promise is added by way of recommendation, the better to remind us how pleasing to God is the submission which is here required. Paul applies that stimulus to rouse us from our lethargy, when he calls this the first commandment with promise; the promise contained in the First Table not being specially appropriated to any one commandment, but extended to the whole law. Moreover, the sense in which the promise is to be taken is as follows:—The Lord spoke to the Israelites specially of the land which he had promised them for an inheritance. If, then, the possession of the land was an earnest of the divine favour, we cannot wonder if the Lord was pleased to testify his favour, by bestowing long life, as in this way they were able long to enjoy his kindness. The meaning therefore is: Honour thy father and thy mother, that thou may be able, during the course of a long life, to enjoy the possession of the land which is to be given thee in testimony of my favour. But, as the whole earth is blessed to believers, we justly class the present life among the number of divine blessings. Whence this promise has, in like manner, reference to us also, inasmuch as the duration of the present life is a proof of the divine benevolence toward us. It is not promised to us, nor was it promised to the Jews, as if in itself it constituted happiness, but because it is an ordinary symbol of the divine favour to the pious. Wherefore, if any one who is obedient to parents happens to be cut off before mature age (a thing which not infrequently happens), the Lord nevertheless adheres to his promise as steadily as when he bestows a hundred acres of land where he had promised only one. The whole lies in this: We must consider that long life is promised only in so far as it is a blessing from God, and that it is a blessing only in so far as it is a manifestation of divine favour. This, however, he testifies and truly manifests to his servants more richly and substantially by death.
Source
source-manifest/institutes— Calvin, Institutes of the Christian Religion, tr. Beveridge 1845 (PD)- evidence_grade: D_doctrinal_textbook