Paul likens the people in the church to the contents of the home of a rich merchant.  In that house, gold bowls and silverware were for serving food at the table; they were valuable and intended to last.  By contrast, wooden and pottery containers were used for dirty jobs: they were contaminated and had no lasting value.  Which of those would the Master of the house like brought to the table?  Obviously - only the gold and silver containers.  They would please the Master and be useful to feed his family and guests.
 
So Paul urged Timothy to ensure that impure and untrue teaching was given no place of honour in the church.  It would make God’s family spiritually ill and poison the guests.  Timothy would fulfil his responsibility in protecting the purity of the church by keeping his own life and teaching in line with that of the Apostle Paul and ensuring that all the members of the church did the same (1 Timothy 4:16).

From the way Paul was writing, he expected that the believers would aim to be pure for the Master’s use – and would be responsible to ‘cleanse themselves’.  What does that mean?  Surely only God can change us from the inside?  Yes, He alone can cleanse us from our sins, but we need to confess them (1 John 1:9).  Yes, only God can make us His children, but we still need to welcome Him (John 1:12).  Only God can take away a heart of stone and give us a heart of flesh (Ezekiel 36:26) but some intentional action is required to cooperate with God and choose to put off the way of life (Ephesians 4:22-24).
 
Every follower of Jesus knows how easily they can be pulled away from the truth: accepting some little wrong idea or making up something that God has never spoken.  Usually we follow others in this, which is why the leaders who oversee the church must not tolerate false teaching, it will only spread … and as more people believe lies they will encourage others to do the same and live in an ungodly way.  The question for us all to ask is, ‘Will this please my Master; will it nourish His family and bring new life to His guests?’ and find out what will please the Lord (Ephesians 5:10).