Final answer:
Paul emphasizes that 'the Lord knows those who are His' to reassure believers and separate them from false teachers.
Step-by-step explanation:
The emphasis on the phrase 'the Lord knows those who are His' is found in the Bible, specifically in 2 Timothy 2:19. In this context, Paul is addressing the issue of false teachers and their influence on the Christian community. By emphasizing that 'the Lord knows those who are His,' Paul is reassuring believers that God is aware of who truly belongs to Him and will separate them from those who claim to be followers but are actually false. This reassurance provides comfort and encouragement to genuine believers, reminding them of God's sovereignty and discernment.