What is the meaning of “Do not grieve the Holy Spirit of God by whom you were sealed for the day of redemption” (Eph. 4:30)?

St. John Chrysostom says, “He it is who marks us as a royal flock; He, who separates us from all former things; He, who suffers us not to lie among them that are exposed to the wrath of God — and do you grieve Him? Look how startling are his words there; For he that rejects, says he, rejects not man, but God: and how cutting they are here, Grieve not the Holy Spirit, says he, in whom you were sealed. Let this seal then abide upon your mouth, and never destroy the impression. A spiritual mouth never utters a thing of the kind. Say not, It is nothing, if I do utter an unseemly word, if I do insult someone, it is nothing. For this very reason is it a great evil, because it seems to be nothing … You have a spiritual mouth. Think what words you uttered immediately upon being born, — what words are worthy of your mouth. You call God, Father, and do you straightway revile your brother? … Now the God of peace keep both your mind and your tongue, and fence you with a sure fence, even His fear, through Jesus Christ our Lord, with whom to the Father, together with the Holy Spirit, be glory forever. Amen.”¹⁴³⁵

St. Macarius the Great says, “If a servant comes into a palace, to be employed upon the vessels used there, he takes of what belongs to the king he himself has nothing to bring and ministers to the king with the king's own vessels. Here he needs much intelligence and judgment, that he may make no mistake in serving, by bringing one dish to the royal table when he should bring another, but should serve the courses, first and last, in the right succession. If through ignorance and want of judgment he does not serve the king in the right order, it is as much as his place and life are worth. In like manner a soul which is serving God in grace and the Spirit requires much discretion and knowledge, that it may commit no fault with the vessels of God, that is, in the service of the Spirit, by not keeping its own will in harmony with grace.”¹⁴³⁶

1435 St. John Chrysostom, Homilies on Ephesians 14 (NPNF I/13:120).

1436 St. Macarius the Great, Fifty Spiritual Homilies of St. Macarius the Egyptian , trans., A. J. Mason (London: Society for Promoting Christian Knowledge, 1921) Homily 15.5: p. 108.