Isaiah 55:11

So shall my word be that goeth forth out of my mouth
My good word, as the Targum; this may either be understood of Christ, the eternal Word, who is called the Word of God, and may be said to go forth out of his mouth, being spoken of by all his holy prophets, since the world began, whose coming was like the rain or snow, ( Hosea 6:3 ) , he came from heaven, from his Father there, and as a free gift of his, and in consequence of a decree, as the rain does; the manner of his coming, like that, was suddenly, gratefully, and with great efficacy, watering his people with his grace, through the ministry of the word, and making them fruitful; and though he returned to heaven again, yet not empty, without fruit and effect; he produced a large harvest of souls, and procured all blessings of grace for them, and accomplished the whole will and pleasure of God, in effecting the salvation of his people; and the pleasure of the Lord prospered in his hand: or else it may be interpreted of God's word of promise; the promises are made in heaven, and come from thence as the rain and snow do; are the gifts of God's grace; are very refreshing and reviving, as rain to the earth; and are always effectual, being yea and amen in Christ Jesus; and being made good, fulfil purposes, or the good will and pleasure of God; particularly promises concerning Christ, pardon and peace through him; such as are given forth in this chapter: or rather it may be meant of the word of the Gospel, which is of God; comes from heaven; is a blessing grace; falls according to divine direction here and there; tarries not for the expectations, desires, or deserts of men; falls in great plenty; and is a blessing wherever it comes: it is the means of softening the hard hearts of men; of cooling the conscience set on fire by the law, and allaying the heat of divine wrath there; and of refreshing and reviving drooping, disconsolate, and weary souls: it is the means of the first buddings of grace in the Lord's people, and of the larger exercises and flourishings of it, and of all fruitfulness in good works: it is productive of seed to Christ the sower, and fruit to his ministers who labour under him, and of bread to the eater, the believer, whom it furnishes with the bread of life to feed upon by faith: it shall not return to me void;
it is accompanied with a divine energy; it is the power of God to salvation: but it shall accomplish that which I please;
in the conversion of sinners, and comfort of saints: and it shall prosper in the thing whereto I sent it:
whether it be the savour of life unto life, or the savour of death unto death; whether for the quickening of sinners, and reviving of saints; or whether for the hardening of men, and leaving them without excuse to perish in their sins, both in the Jewish and Gentile world.