That thy trust may be in the Lord. The Greek and Latin versions make this clause depend on the preceding verse. It is better to consider it as dependent on the second hemistich, the fact of instruction being placed after the statement of its object.
All the instruction herein afforded is meant to teach that entire confidence in the Lord which, as soon as his will is known and understood, leads a man to do it at any cost or pains, leaving the result in God's hands.
I have made them known to thee this day, even to thee. The repetition of the personal pronoun brings home the teaching to the disciple, and shows that it is addressed, not merely to the mass of men, but to each individual among them, who thus becomes responsible for the use which he makes of it (comp.
Proverbs 23:15). The expression, "this day," further emphasizes the exhortation. The learner is not to remember vaguely that some time or other he received this instruction, but that on this particular day the warning was given.
So in Hebrews 3:7, Hebrews 3:13 we read, "As the Holy Ghost saith, Today if ye will hear his voice, harden not your hearts ….Exhort one another daily, so long as it is called Today, lest any of you be hardened by the deceitfulness of sin."
Septuagint, "That thy hope may be in the Lord, and he may make thy way known unto thee." Cheyne ('Job and Solomon') quotes Biekell's correction of this verse, "That thy confidence may be in Jehovah, to make known unto thee thy ways;" but the alteration seems arbitrary and unnecessary.