4:1 Testificor coram Deo, et Jesu Christo, qui judicaturus est vivos et mortuos, per adventum ipsius, et regnum ejus: [n. 129]
4:1 I charge you, before God and Jesus Christ, who shall judge the living and the dead, by his coming and his kingdom: [n. 129]
4:2 praedica verbum, insta opportune, importune: argue, obsecra, increpa in omni patientia, et doctrina.
4:2 Preach the word: be instant in season, out of season: reprove, entreat, rebuke in all patience and doctrine.
4:3 Erit enim tempus, cum sanam doctrinam non sustinebunt, sed ad sua desideria coacervabunt sibi magistros, prurientes auribus, [n. 132]
4:3 For there shall be a time when they will not endure sound doctrine but, according to their own desires, they will heap to themselves teachers having itching ears: [n. 132]
4:4 et a veritate quidem auditum avertent, ad fabulas autem convertentur. [n. 140]
4:4 And will indeed turn away their hearing from the truth, but will be turned unto fables. [n. 140]
4:5 Tu vero vigila, in omnibus labora, opus fac evangelistae, ministerium tuum imple. Sobrius esto. [n. 141]
4:5 But be vigilant, labor in all things, do the work of an evangelist, fulfill your ministry. Be sober. [n. 141]
Read the comments of St Thomas Aquinas here