You are right; the only thing God cannot do is anything that is wrong or evil—including telling a lie. God is absolutely holy and pure, and everything He does is in line with His perfect character. The Bible says, “As for God, his way is perfect: The Lord’s word is flawless” (Psalm 18:30).
What if God were not this way? What if He was honest one minute and dishonest the next (like some of the ancient mythological deities)? Or what if He promised to save us if we put our trust in Christ as our Savior (as the Bible declares)—but then went back on His promise? You know the answer: we could never trust Him or rely on Him for anything. Nor would it make sense to pray to Him, because we never could be sure of the answer.
But God is not this way! God is absolutely trustworthy—and because He is, we can be confident that every promise He has made in His Word will be fulfilled. Most of all, we can be confident that Jesus Christ was who He said He was: The eternal Son of God, sent from Heaven to save us from our sins.
Do you trust Christ, and Christ alone, for your eternal salvation? When our trust is in Him, we know that nothing “in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord” (Romans 8:39).