Acts 20:28-31
Around AD 56, the apostle Paul prophesied that upon his departure, false teachers would infiltrate the Ephesian fellowship to lead them astray, and men from among the congregation would also rise up to corrupt the divinely established doctrinal truths (see also Ephesians 5:6-7). Although the Ephesians deserved praise for their dedication to Christ (Ephesians 1:15), Paul feared they would neglect their duty to love one another.
Soon after his exit, his dire prediction came true. Disputes arose, leading to division. Many drifted away, and the loving fellowship of earlier years began to wane (I Timothy 1:18-20; 4:1-3). Paul ordered Timothy to remain in Ephesus to combat these very problems (I Timothy 1:3-7), emphasizing that it was necessary to promote “love from a pure heart, from a good conscience, and from sincere faith,” from which many in the early church had strayed (Galatians 1:6-7).
Martin G. Collins
First Love (Part One)

Calling these future apostates "savage wolves," and as Jude later terms them "brute beasts," conjures the idea that man's animalistic nature drives these false teachers. Their bodies, desires, and lusts—not merely their minds—compel them, craving satisfaction not only in carnal needs but also in gain, standing atop the pack, glory, and prestige. Around AD 56, Paul prophesied that upon his departure false teachers would infiltrate the Ephesian fellowship, and men from among them would rise to corrupt divine truth. Soon disputes, division, and drifting occurred, prompting Paul to station Timothy there. Knowing the history of God's truth, Paul recognized that people cannot hold to it long. He urged special attention to feeding the flock. This has occurred frequently and will intensify through the Great Tribulation.