Why should the truth set one to falling? Because truth is defined in eternity to be Jesus, the Creator God. Those who appose Him also appose all that is right, just, verity, and knowledge itself. All this came from Him.
Notice in the verses below, the nature and character of our God. Verse 4 defines his nature. Notice he is both truth and a rock. When one denies truth, their obstacle is the rock. And people wonder why truth should set one falling?
Deu 32:1 Give ear, O ye heavens, and I will speak; and hear, O earth, the words of my mouth.
Deu 32:2 My doctrine shall drop as the rain, my speech shall distil as the dew, as the small rain upon the tender herb, and as the showers upon the grass:
Deu 32:3 Because I will publish the name of the LORD: ascribe ye greatness unto our God.
Deu 32:4 He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is he.
Deu 32:5 They have corrupted themselves, their spot is not the spot of his children: they are a perverse and crooked generation.
Here is definition of the ways of God, perfection (the flawlessness of the LORD). He is again identified as a rock. In Psalm 18:46 below, the term rock is tied to salvation. The rock can then be that over which one falls or that which is a protection.
2Sa 22:31 As for God, his way is perfect; the word of the LORD is tried: he is a buckler to all them that trust in him.
2Sa 22:32 For who is God, save the LORD? and who is a rock, save our God?
And David, later king of Israel said, “Psa 18:46 The LORD liveth; and blessed be my rock; and let the God of my salvation be exalted.
Below is the commentary that people try to enter into the salvation by the “works of the law”. But the Scriptures say one must come by faith. Righteousness is attained by receiving the righteousness extended by the Savior, Jesus Christ. One must go to him – seeking, asking. Jesus extends to the earnest soul that payment of debt for sin which he cannot earn or pay off out of his own strength.
Rom 9:29 And as Esaias said before, Except the Lord of Sabaoth had left us a seed, we had been as Sodoma, and been made like unto Gomorrha.
Rom 9:30 What shall we say then? That the Gentiles, which followed not after righteousness, have attained to righteousness, even the righteousness which is of faith.
Rom 9:31 But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness.
Rom 9:32 Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumbling stone;
Rom 9:33 As it is written, Behold, I lay in Sion a stumbling stone and rock of offence: and whosoever believeth on him shall not be ashamed.
So the stone which may be the instrument of the fall of some, is also the stone by which one may find solace. He is the one who will either be turned to or he will be the one over whom one will stumble and find their shame and hurt. The end result for the unbelieving, the disobedient is below in Isa 8:15.
1Pe 2:6 Wherefore also it is contained in the scripture, Behold, I lay in Sion a chief corner stone, elect, precious: and he that believeth on him shall not be confounded.
1Pe 2:7 Unto you therefore which believe he is precious: but unto them which be disobedient, the stone which the builders disallowed, the same is made the head of the corner,
1Pe 2:8 And a stone of stumbling, and a rock of offence, even to them which stumble at the word, being disobedient: whereunto also they were appointed.
Isa 8:13 Sanctify the LORD of hosts himself; and let him be your fear, and let him be your dread.
Isa 8:14 And he shall be for a sanctuary; but for a stone of stumbling and for a rock of offence to both the houses of Israel, for a gin and for a snare to the inhabitants of Jerusalem.
Isa 8:15 And many among them shall stumble, and fall, and be broken, and be snared, and be taken.