Proverbs 20:18 New English Translation

¹⁸Plans^[a] are established by counsel,
so^[b] make war^[c] with guidance.

Proverbs 20:18 tn The noun form is plural, but the verb is singular, suggesting either an abstract plural or a collective plural is being used here.
Proverbs 20:18 tn The clause begins with vav (ו) on “with guidance.” But the clause has an imperative for its main verb. One could take the imperfect tense in the first colon as an imperfect of injunction, and then this clause would be also instructional. But the imperfect tense is a Niphal, and so it is better to take the first colon as the foundational clause and the second colon as the consequence (cf. NAB): If that is true, then you should do this.
Proverbs 20:18 sn There have been attempts by various commentators to take “war” figuratively to mean life’s struggles, litigation, or evil inclinations. But there is no need and little justification for such interpretations. The proverb simply describes the necessity of taking counsel before going to war.

New English Translation (NET)