The DR number, Diederich Rank, refers to the highest number in Diederich's frequency listing, which you can see here: Diederich Ranking.
DR 146. Petenti dabitur. ~ Note: Note the use of the future here: "It will be given..." The reference is to the power of prayer: what you ask God for in your prayers will be given, dabitur. You can find the Latin saying invoked by Pascal in his Pensées, 514. Compare Matthew 7.7: Petite, et dabitur vobis, "Ask, and it will be given to you."
DR 148. Magna opera Domini. ~ Note: The words are from Psalms, 110.
DR 148. Quid opus est verbis? ~ Note: The phrase opus est takes an ablative complement: verbis. We would say in English, "What need is there of words?"
DR 148. Non verbis, at factis opus est. ~ Note: Note the parallel structure: Non verbis (opus est), at factis opus est.
DR 148. Qui nihil amat, quid ei homini opus vita est? ~ Note: Here you have both the dative (ei homini) and ablative (vita) complements of the phrase opus est.
DR 150. Ducit Dominus. ~ Note: This is the motto of the Dirom family.
DR 150. Non ducor: duco. ~ Note: This proverb plays very nicely on the active, duco, and passive, ducor, forms of the verb. It serves as the motto of the city of São Paulo in Brazil.
DR 151. Quod verum est, meum est. ~ Note: This is a sentiment expressed by Seneca in his Epistulae Morales, 1.
DR 151. Quaerimus verum. ~ Note: The neuter adjective verum can be used substantively to mean "the true (thing)," "the truth," etc. This is the motto of Bethany College.
DR 151. Verum non dicimus, ne audiamus. ~ Note: This is one of the sayings collected by Publilius Syrus.