As for you, always be sober-minded, endure suffering, do the work of an evangelist, fulfill your ministry.
To be watchful in all things really means to be sober in all things. Timothy should be serious in his work, temperate, and well-balanced. He should not shun afflictions but should suffer willingly whatever hardships might come to him in his service for Christ.
There is some difference of opinion as to the expression do the work of an evangelist. Some think that Timothy actually was an evangelist and that here Paul was simply telling him to carry out this ministry. Others think that Timothy did not have the gift of evangelism, being perhaps a pastor or teacher, but that this should not prevent him from preaching the gospel as occasion arose. It seems likely that Timothy actually was an evangelist and that Paul's words are simply an encouragement for him to be all that evangelists should be.
In every respect, he should fulfill his ministry, devoting his finest talents to all the demands of his service.