Titus 1, 1;2
2 in hope of eternal life which God, who cannot lie, promised before time began,
Hebrews 6;18
18 that by two immutable things, in which it is impossible for God to lie, we might have strong consolation, who have fled for refuge to lay hold of the hope set before us.
Revelation 21;8
all liars shall have their part in the lake which burns with fire and brimstone, which is the second death
If God lied, wouldn't that make him a hypocrite?
Also how could you have faith in God, if you don't know when he is lying and when he is telling the truth.
A logic question you could ask yourself, what if the only true thing God have said in the Bible is "Thou shalt not steal" everything else is a lie, how could you demonstrate to me, that what im saying is not true, if God is able to lie?