Surely goodness and mercy shall follow me - God will bestow them upon me. This is the “result” of what is stated in the previous verses. The effect of God’s merciful dealings with him had been to lead his mind to the assurance that God would always be his shepherd and friend; that He would never leave him to want.
All the days of my life - Through all its changes; in every variety of situation; until I reach its close. Life indeed would end, and he does not venture to conjecture when that would be; but as long as life should continue, he felt confidently assured that everything needful for him would be bestowed upon him. The language is the utterance of a heart overflowing with joy and gratitude in the recollection of the past, and full of glad anticipation (as derived from the experience of the past) in regard to the future.
And I will dwell in the house of the Lord for ever - Margin, as in Hebrew: “to length of days.” The expression, I think, does not refer to eternity or to heaven, but it is parallel with the former expression “All the days of my life;” that is, he would dwell in the house of the Lord as long as he lived - with the idea added here, which was not in the former member of the sentence, that his life would be long, or that he hoped and anticipated that he would live long on the earth. The phrase used here, “I will dwell in the house of the Lord,” is one that is several times employed in the Psalms as indicative of the wish of the psalmist. Thus, in Psalms 27:4, “One thing have I desired of the Lord, that will I seek after; that I may dwell in the house of the Lord all the days of my life.” Psalms 26:8, “lord, I have loved the habitation of thy house, and the place where thine honor dwelleth.” Psalms 65:4, “blessed is the man whom thou choosest, and causest to approach unto thee, that he may dwell in thy courts.”
Psalms 84:4, “blessed are they that dwell in thy house.” (Compare also Psalms 87:1, Psalms 87:3,10). The “language” here is obviously taken from the employment of those who had their habitation near the tabernacle, and afterward the temple, whose business it was to attend constantly on the service of God, and to minister in his courts. We are not to suppose of David that he anticipated such a residence in or near the tabernacle or the house of God; but the meaning is, that he anticipated and desired a life as if he dwelt there, and as if he was constantly engaged in holy occupations. His life would be spent as if in the constant service of God; his joy and peace in religion would be as if he were always within the immediate dwelling-place of the Most High. This expresses the desire of a true child of God. He wishes to live as if he were always engaged in solemn acts of worship, and occupied in holy things; he desires peace and joy in religion as if he were constantly in the place where God makes his abode, and allowed to partake of his smiles and friendship. In a very important sense it is his privilege so to live even on earth; it will certainly be his privilege so to live in heaven: and, full of grateful exultation and joy, every child of God may adopt this language as his own, and say confidently, “Goodness and mercy will follow me all the days of my life here, and I shall dwell in the house of the Lord forever,” for heaven, where God dwells, will be his eternal home.