Do a Bible study, check all the instances about telling lies and from there build up your exhortation, then you can include those extraordinary exceptions if you reckon they will help the listeners. As an exhortation perhaps these could be left out, in other kind of presentation I think they must be included, but it's up to you of course.
FOR THE YOUNG DISCIPLE
TAKING THE BIBLE SERIOUSLY
9—NO LYING
YAHWEH is truth. Therevelation of the character of God by word and action in the O.T. taught the real meaning of truth and faithfulness (Exod. 34:6; Psa. 31:5; 89:1, 2, 5, 8, 14, 24, 33, 49. Jer. 10:10). The prophets, speaking for God, continually referred the people to His divine standard (Isa. 59:3–4; Jer. 9:3; Hosea 10:13; Zech. 8:16–17). Jesus is the truth; in him the standards of God are seen in action (John 1:14, 17; 14:6). Those who accept these standards as their own must appreciate that a sincere attempt to put them into practice will provide the only basis for correction of faults. Lying is the negation of God’s principle of truth; no other explanation will do (Prov. 6:19; Psa. 15:1–3; Ezek. 13:17–19).
Biblical instruction infiltrates every aspect of life:
— bearing false witness is condemned consistently throughout the Bible (Exod. 20:16; Deut. 5:20; Matt. 19:18; Rom. 13:9).
— lying to and against others is another way of showing disrespect for others, not merely a social rule, but because God has determined the ideal way for men to live together (Eph. 4:25; Psa. 27:12; 35:11; Prov. 25:18; 24:28; 14:25).
— the “two witness” principle must be used to safeguard the truth, not respect of persons. (Num. 35:30; Deut. 17:6; 19:15; Matt. 18:16; 2 Cor. 13:1; 1 Tim 5:19; Heb. 10:28).
— silence is condemned when truth is at stake (Lev. 5:1).
— human nature is the root cause to be tackled (Psa. 58:3; 62:4; Matt. 15:19).
— the effects of failure to apply God’s standards are seen in many ways:
a. lying leads to falsehood in the way of life (Ezek. 13:8; Amos 2:4).
b. this necessarily leads away from God, and those who teach this are particularly condemned (Ezek. 13:9; 21:29; 22:28; Isa. 9:15; Jer. 14:14; 23:25; 23:32; 27:10, 14, 16, 18; Zech. 10:2).
c. lying readily becomes associated with violence, misrule and adultery, because the impact of God’s way is nullified (Hos. 12:1; Prov. 29:12; Jer. 23:14).
d. lying is malicious and destructive (Exod. 23:1; Tim. 3:11; 2 Cor. 12:20; 1 Pet. 2:1). The only positive antidote is prayer:
“Remove far from me vanity and lies” (Prov. 30:8).
(Vol. 113: The Christadelphian : Volume 113. 2001, c1976. The Christadelphian, volume 113. (electronic ed.). Logos Library System (Vol. 113, Page 268). Birmingham: Christadelphian Magazine & Publishing Association.)