<p>2:19- see on Mt. 7:23.</p><p><em>However the firm foundation of God stands sure, having this seal: The Lord knows those that are his. And: Let every one that names the name of the Lord depart from unrighteousness- </em>The implication is that despite false teachers, those known by the Lord Jesus? are on God's firm foundation and will not be shifted from it. But that firm foundation, as Paul uses the metaphor in Corinthians, is a living relationship with the Lord Jesus. Those who know Him, and are known by Him, are thereby in relationship with Him. And having named His Name, calling it upon themselves in baptism, they will &quot;depart from unrighteousness&quot;. Any teaching which leads them to unrighteous behaviour will be intuitively rejected by them. In expounding 1 Timothy 2, I noted there were many allusions there to the idol temples of Ephesus, especially the temple of Artemis. The reference to firm foundations likewise refers to that same temple. The two &quot;seals&quot; quoted are likely &quot;faithful sayings&quot; popular amongst the illiterate of the first century Christian community. The seal of God is in the mind, &quot;in the forehead&quot; (Rev. 9:4), likely a reference to the gift of the Holy Spirit in the heart / mind of every believer. This is what knowing the Lord and being known by Him is all about- living relationship with the Lord Jesus through the gift of His Spirit. And the function of that Spirit in practice will be a departure from unrighteousness. The term &quot;depart from&quot; usually refers to departing from persons; and this is the context of this verse- an appeal to depart from false teachers and their teachings. The same word has been used in 1 Tim. 6:5 about withdrawing from those who taught like this.</p>