job 1:5 And it was so, when the days of their feasting were gone about, that Job sent and sanctified them, and rose up early in the morning, and offered burnt offerings according to the number of them all: for Job said, It may be that my sons have sinned, and cursed God in their hearts. Thus did Job continually. - Free Bible Online

      5. when the days of their feasting were gone about--that is, at the end of all the birthdays collectively, when the banquets had gone round through all the families.
      Job . . . sanctified--by offering up as many expiatory burnt offerings as he had sons (Le 1:4). This was done "in the morning" (Ge 22:3; Le 6:12). Jesus also began devotions early (Mr 1:35). The holocaust, or burnt offering, in patriarchal times, was offered (literally, "caused to ascend," referring to the smoke ascending to heaven) by each father of a family officiating as priest in behalf of his household.
      cursed God--The same Hebrew word means to "curse," and to "bless"; GESENIUS says, the original sense is to "kneel," and thus it came to mean bending the knee in order to invoke either a blessing or a curse. Cursing is a perversion of blessing, as all sin is of goodness. Sin is a degeneracy, not a generation. It is not, however, likely that Job should fear the possibility of his sons cursing God. The sense "bid farewell to," derived from the blessing customary at parting, seems sufficient (Ge 47:10). Thus UMBREIT translates "may have dismissed God from their hearts"; namely, amid the intoxication of pleasure (Pr 20:1). This act illustrates Job's "fear of God" (Job 1:1).

JFB.