Let us not sleep. — The metaphor here expresses not so much actual sin (Ephesians 5:14) as carelessness in spiritual and moral things. “Let us not say, ‘Peace and safety,’ and resign ourselves to indifference about Christ’s coming.” St. Paul (as always) indicates that it was possible for “children of light” to be converted back into “children of darkness.”
Others. — Rather, the rest, as in 1 Thessalonians 4:13 : so also Romans 11:7; Ephesians 2:3.
Watch and be sober. — The comparison of night now suggests to the writer another thought besides that of sloth, namely, that of dissipation. Christians are not to turn day into night by debauchery any more than by sleep.