In this pericope Paul reminded Timothy of the apostasy that Jesus Christ had foretold to equip him to identify and deal with it. [1][source]
" 1 Timothy 4:1-5 does not begin a new topic. Paul, who has given his instructions on the true understanding of law, grace, and salvation ( 1 Timothy 1:3 to 1 Timothy 2:7) and on church behavior and leadership ( 1 Timothy 2:8 to 1 Timothy 3:13) and has paused to put his instructions into proper perspective ( 1 Timothy 3:14-16), now concludes by pointing out that these types of problems should have been expected because the Holy Spirit had clearly prophesied their occurrence ..." [2][source]