But om a great house there are not only vessels of gold and silver, but also of wood and of earth; and some to honor, and some to dishonor. If a man therefore purge himself of these, he shall be a vessel unto honor, sanctified, and fit for the master’s use and prepared unto every good work. (2 Tim 2:20-21)
This text gives us the secret of how to be useful to God. There is only one way; that is to separate from sin. In doing so, one will be a vessel for His honor. Be therefore Holy, as He is holy.