How do we know that the Word of God is truth? Look at these passages:
Psalm 119:160
All your words are true all your righteous laws are eternal.
Isaiah 45:19
I have not spoken in secret, from somewhere in a land of darkness; I have not said to Jacob’s descendants, ‘Seek me in vain.’ I, the Lord, speak the truth; I declare what is right.
And what does the Word tell us about our responsibility to speak and seek the truth?
Zechariah 8:16
These are the things you are to do: Speak the truth to each other, and render true and sound judgment in your courts;
John 4:23
Yet a time is coming and has now come when the true worshipers will worship the Father in the Spirit and in truth, for they are the kind of worshipers the Father seeks.
The Apostle Paul was speaking to the Roman church to prove to them that God has revealed Himself to all people, but that not all people will accept His gift of salvation because that would mean that they would have to admit that they need a Savior. Hear what he tells them:
Romans 1:20-25
For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.
For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened. Although they claimed to be wise, they became fools and exchanged the glory of the immortal God for images made to look like a mortal human being and birds and animals and reptiles.
Therefore God gave them over in the sinful desires of their hearts to sexual impurity for the degrading of their bodies with one another. They exchanged the truth about God for a lie, and worshiped and served created things rather than the Creator—who is forever praised. Amen.
As Christians, we are told that the world will know us by our love. As ambassadors here on earth, we are to show God's love to everyone. But today, many who call themselves Christians are not reflections of God's love. They promote violence and hatred based on their own value system, they are confused about what is morally right and wrong and they are quick to condemn sins in others, but fail to admit their own sins. True Christians are called to speak the truth, but to speak it with a spirit of love.
Love does not delight in evil, but rejoices with the truth. 1 Corinthians 13:6
Instead, speaking the truth in love, we will grow to become in every respect the mature body of him who is the head, that is, Christ. Ephesians 4:15
It really shouldn't come as a surprise to believers that the enemy is deceiving so many people. In fact, the Bible tells us that this will happen before the return of Christ.
Don’t you remember that when I was with you I used to tell you these things? And now you know what is holding him back, so that he may be revealed at the proper time. For the secret power of lawlessness is already at work; but the one who now holds it back will continue to do so till he is taken out of the way. And then the lawless one will be revealed, whom the Lord Jesus will overthrow with the breath of his mouth and destroy by the splendor of his coming. The coming of the lawless one will be in accordance with how Satan works. He will use all sorts of displays of power through signs and wonders that serve the lie, and all the ways that wickedness deceives those who are perishing. They perish because they refused to love the truth and so be saved. 2 Thessalonians 2:5-10
But mark this: There will be terrible times in the last days. People will be lovers of themselves, lovers of money, boastful, proud, abusive, disobedient to their parents, ungrateful, unholy, without love, unforgiving, slanderous, without self-control, brutal, not lovers of the good, treacherous, rash, conceited, lovers of pleasure rather than lovers of God— having a form of godliness but denying its power. Have nothing to do with such people.
They are the kind who worm their way into homes and gain control over gullible women, who are loaded down with sins and are swayed by all kinds of evil desires, always learning but never able to come to a knowledge of the truth. 2 Timothy 3:1-7
Many will follow their depraved conduct and will bring the way of truth into disrepute. 2 Peter 2:2
If we claim to be without sin, we deceive ourselves and the truth is not in us. 1 John 1:8
But those of us who have accepted Jesus as our Lord and Savior can have hope, even in these troubled times. Because we have God's Holy Spirit living within us. The things of God are spiritually discerned and cannot be understood unless we have His Spirit living in us.
Jesus replied, “Very truly I tell you, no one can see the kingdom of God unless they are born again." John 3:33
If we accept God's Word as the truth, then we also have to accept Jesus' because in John 14:6 He said, "I Am the Way, the Truth and the Life. No one comes to the Father except through me."