If he cannot find anyone, then he shall fast two consecutive months before any sexual contact between them. If he cannot, then he shall feed sixty poor people. That is so you would acknowledge God and His messenger. These are the limits set by God. Those who do not appreciate have incurred a painful retribution.
Translation endnotes
[58:4] The beginning of the verse, "faman lam yajid" (literally: as for the one who does not find), clearly indicates that the slaves instructed to be freed in the previous verse are not expected to belong to muslims. Otherwise, an expression such as "if one does not possess" should have been used. Slavery is prohibited by the Quran as one of the greatest sins. See: 3:79; 4:3,25,92; 5:89; 8:67; 24:32-33; 58:3-4; 90:13; 2:286; 12:39-42; 79:24.