Vincent's NT Word Studies
1. Comp. the beginning of 1 Timothy 4.This know (touto ginwske). The phrase N.T.o . Comp. Paul's ginwskein uJmav boulomai I would have you to know, Philippians. i. 12; and qelw de uJmav eijdenai I would you should know, 1 Corinthians. xi. 3.
In the last days (ep escataiv hmeraiv). The phrase only here in Pastorals, Acts ii. 17, James. v. 3. Similar expressions are ejn kairw ejscatw in the last season, 1 Pet. i. 5: ejp' ejscatou twn cronwn at the last of the times, 1 Pet. i. 20: ejp' ejscatou cronou at the last time, Jude xviii. ejp' ejscatwn twn hJmerwn at the last of the days, 2 Pet. iii. 3: ejn uJsteroiv kairoiv in the latter seasons, 1 Tim. iv. 1. The times immediately preceding Christ's second appearing are meant. Comp. Heb. i. 2; James. v. 3.
Perilous times (kairoi calepoi). Only here and Matt. viii. 28. Lit. hard times: schwere Zeiten. Kairov. denotes a definite, specific season. See on Matt. xii. 1; Acts i. 17.
Shall come (ensthsontai). Or will set in. Mostly in Paul. Only here in Pastorals. See on Gal. i. 4.
Robertson's NT Word Studies
3:1 {Know this } (touto ginwske). See #1Co 11:3; Php 1:12. {In the last days} (en escatais hemerais). See #Jas 5:3; 1Ti 4:1. {Grievous} (calepoi). Hard. See #Eph 5:16. {Shall come} (enstesontai). Future middle of enistemi (intransitive use), old verb, to stand on or be at hand, as in #2Th 2:2.