Surely he shall deliver thee from the snare of the fowler - The snare or gin set for catching birds; meaning, here, that God would save him from the purposes of wicked people; such purposes as might be compared with the devices employed to catch birds. On the meaning of the figure used here, see the notes at Psalm 18:5.
And from the noisome pestilence - The "fatal" pestilence; the pestilence that spreads death in its march. That is, he can prevent its coming upon you; or, he can save you from its ravages, while others are dying around you. This promise is not to be understood as absolute, or as meaning that no one who fears God will ever fall by the pestilence - for good people "do" die at such times as well as bad people; but the idea is, that God "can" preserve us at such a time and that, as a great law, he will be thus the protector of those who trust him. It is to be remembered that in times of pestilence (as was the case during the prevalence of the Asiatic cholera in 1832 and 1848), very many of the victims are the intemperate, the sensual, the debased, and that a life of this kind is a predisposing cause of death in such visitations of judgment. A large part of those who die are of that number. From the danger arising from this cause, of course the virtuous, the temperate, the pious are exempt; and this is one of the methods by which God saves those who trust in him from the "noisome pestilence." Religion, therefore, to a considerable extent, constitutes a ground of security at such times; nor is there any reason to doubt that, in many cases also, there may be a special interposition protecting the friends of God from danger, and sparing them for future usefulness. The promise here is substantially that general promise which we have in the Scriptures everywhere, that God is the Protector of his people, and that they may put their trust in him.

Surely he shall deliver thee - If thou wilt act thus, then the God in whom thou trustest will deliver thee from the snare of the fowler, from all the devices of Satan, and from all dangerous maladies. As the original word, דבר dabar, signifies a word spoken, and deber, the same letters, signifies pestilence; so some translate one way, and some another: he shall deliver thee from the evil and slanderous word; he shall deliver thee from the noisome pestilence - all blasting and injurious winds, effluvia, etc.

Surely he shall deliver thee from the (c) snare of the fowler, [and] from the noisome pestilence.
(c) That is, God's help is most ready for us, whether Satan assails us secretly which he calls a snare, or openly which is here meant by the pestilence.

Surely he shall deliver thee from the snare of the fowler,.... These are the words of the psalmist, either speaking to himself, for the encouragement of his own faith and trust in the Lord; or to the man that dwells in the secret place, and under the shadow of the most High; which latter seems most agreeable; though Cocceius thinks they are the words of God in one of his Persons, speaking of another divine Person that should deliver such that trust in him: the Targum makes them to be the words of David to Solomon his son. By the "fowler" and his "snare" may be meant either Saul, who laid wait for David, spread snares for him, and hunted him as a partridge on the mountains, from whom he was delivered; or rather any tyrannical enemy and persecutor of the saints, who lay snares for them; and these are broken by the Lord, and so they escape, as a bird out of the hands of the fowler, Psalm 124:6 or it may, best of all, be understood of Satan and his temptations, which are as snares that he lays to catch the people of God in, and from which they are delivered by the power and grace of God; see 1-Timothy 3:7.
and from the noisome pestilence; the most pernicious and destructive one; which may be literally understood of any pestilential distemper; from which the Lord, by his powerful providence, sometimes protects his people, when in danger of it: or, spiritually, of the pestilential disease of sin, that noisome and deadly one, the plague of the heart, which is the worst of all plagues; and from the ruinous and destructive effects and consequences of which the Lord saves his saints.

snares . . . [and] . . . noisome pestilence--literally, "plagues of mischiefs" (Psalm 5:9; Psalm 52:7), are expressive figures for various evils.

יקושׁ, as in Proverbs 6:5; Jeremiah 5:26, is the dullest toned from for יקושׁ or יוקשׁ, Psalm 124:7. What is meant is death, or "he who has the power of death," Hebrews 2:14, cf. 2-Timothy 2:26. "The snare of the fowler" is a figure for the peril of one's life, Ecclesiastes 9:12. In connection with Psalm 91:4 we have to call to mind Deuteronomy 32:11 : God protects His own as an eagle with its large strong wing. אברה is nom. unitatis, a pinion, to אבר, Isaiah 40:31; and the Hiph. הסך, from סכך, with the dative of the object, like the Kal in Psalm 140:8, signifies to afford covering, protection. The ἅπαξ λεγ. סחרה, according to its stem-word, is that which encompasses anything round about, and here beside צנּה, a weapon of defence surrounding the body on all sides; therefore not corresponding to the Syriac sḥārtā', a stronghold (סהר, מסגּרת), but to Syriac sabrā', a shield. The Targum translates צנּה with תּריסא, θυρεός, and סחרה with עגילא, which points to the round parma. אמתּו is the truth of the divine promises. This is an impregnable defence (a) in war-times, Psalm 91:5, against nightly surprises, and in the battle by day; (b) in times of pestilence, Psalm 91:6, when the destroying angel, who passes through and destroys the people (Exodus 11:4), can do no harm to him who has taken refuge in God, either in the midnight or the noontide hours. The future יהלך is a more rhythmical and, in the signification to rage (as of disease) and to vanish away, a more usual form instead of ילך. The lxx, Aquila, and Symmachus erroneously associate the demon name שׁד with ישׁוּד. It is a metaplastic (as if formed from שׁוּד morf de) future for ישׁד, cf. Proverbs 29:6, ירוּן, and Isaiah 42:4, ירוּץ, frangetur. Psalm 91:7 a hypothetical protasis: si cadant; the preterite would signify cediderint, Ew. 357, b. With רק that which will solely and exclusively take place is introduced. Burk correctly renders: nullam cum peste rem habebis, nisi ut videas. Only a spectator shalt thou be, and that with thine own eyes, being they self inaccessible and left to survive, conscious that thou thyself art a living one in contrast with those who are dying. And thou shalt behold, like Israel on the night of the Passover, the just retribution to which the evil-doers fall a prey. שׁלּמה, recompense, retribution, is a hapaxlegomenon, cf. שׁלּמים, Isaiah 34:8. Ascribing the glory to God, the second voice confirms or ratifies these promises.

Pestilence - From the pestilence, which like a fowler's snare takes men suddenly and unexpectedly.