Just because you say the truth does not necessarily mean you are truthful according to the Bible but rather it can be a lie. Similarly, a lie can actually be a truth according to God.
Truth that are false
(Deut 32:4) [He is] the Rock, His work [is] perfect; For all His ways [are] justice, A God of truth and without injustice; Righteous and upright [is] He.
(John 8:44) “You are of [your] father the devil, and the desires of your father you want to do. He was a murderer from the beginning, and [does not] stand in the truth, because there is no truth in him. When he speaks a lie, he speaks from his own [resources,] for he is a liar and the father of it.
We know that our God is a God of truth but the devil is not only a liar but the father of lies.
Are the last two witnesses false?
(Matt 26:60-61) but found none. Even though many false witnesses came forward, they found none. But at last two false witnesses came forward and said, “This [fellow] said, ‘I am able to destroy the temple of God and to build it in three days.’ “
(John 2:19) Jesus answered and said to them, “Destroy this temple, and in three days I will raise it up.”
As we see above, the two last witnesses aren’t false. However, Bible does call them false witnesses.
Lies that brings blessings
(Exod 1:19-20) And the midwives said to Pharaoh, “Because the Hebrew women [are] not like the Egyptian women; for they [are] lively and give birth before the midwives come to them.” Therefore God dealt well with the midwives, and the people multiplied and grew very mighty.
Midwives said lies to Pharaoh but God bless them for it because their lies saved lives.
What is Truth?
(John 14:6) Jesus said to him, “I am the way, the truth, and the life. No one comes to the Father except through Me.
(Rev 19:11) Now I saw heaven opened, and behold, a white horse. And He who sat on him [was] called Faithful and True, and in righteousness He judges and makes war.
Christ is the Truth and the fruit of His Spirit is truth. Anything that does not proceed from Him or does not glorify Him is a lie.
(Eph 5:9) for the fruit of the Spirit [is] in all goodness, righteousness, and truth