Charles H. Spurgeon on Psalms 104:4

Who maketh his angels spirits. The words, "creating his angels spirits, "may either mean "creating them spiritual beings, not material beings, "or "creating them winds" —i.e. like the winds, invisible, rapid in their movements, and capable of producing great effects. The last mode of interpretation seems pointed out by the parallelism —"and his ministers" —or, "servants" —who are plainly the same as his angels, —"a flame of fire, "i.e., like the lightning. The statement here made about the angels seems to be this: "They are created beings, who in their qualities bear a resemblance to the winds and the lightning." The argument deduced by Paul, in Heb 2:7, from this statement for the inferiority of the angels is direct and powerful: —He is the Son; they are the creatures of God. "Only begotten" is the description of his mode of existence; made is the description of theirs. All their powers are communicated power; and however high they may stand in the scale of creation, it is in that scale they stand, which places them infinitely below him, who is so the Son of God as to be "God over all, blessed for ever." —John Brown, in "An Exposition of the Epistle to the Hebrews."