1 Timothy 4:16
16 Take heed unto thyself, and unto the doctrine; continue in them: for in doing this thou shalt both save thyself, and them that hear thee.
The Grace New Testament Commentary - 1 Timothy 4:16
4:16 "Take heed to yourself and to the doctrine". To be a good example and a good teacher, Timothy must take heed to himself and to the doctrine, that is, the body of truth entrusted to him by the Apostle Paul. Timothy was to continue in them. Why did Paul use the plural pronoun them when the word doctrine is singular? Surely Paul means for them to stand collectively for all the doctrines, plural. The church leader is not to advance beyond apostolic doctrine. He must continue in them. Otherwise, the flock and the leader himself will be hurt.
For in doing this [in continuing in sound doctrine] Timothy would save both himself and those who hear him. This verse is confusing for those who think that sōzō, the verb translated "save", always, or even typically, refers to deliverance from eternal condemnation. Timothy and the believers he taught were already born again and did not need to do anything to stay born again.
The issue here is spiritual health. The basic sense of sōzō is well-being, wholeness, and health, either physical or spiritual. The church in Ephesus was confronted by men who promoted false doctrines and false practices (cf. 1 Timothy 1:6-11). To remain spiritually well Timothy and his flock needed to be "saved" (delivered) from these false teachings and practices.