Belt of Truth Ephesians 6:10-20
One of the jobs of the devil is to lie to us, the devil even lied to Jesus when He was in the wilderness, but whenever the devil came to Jesus with a lie, Jesus always replied with the truth. Jesus stood firm in the truth when combating temptation. Jesus also tells us to stand firm in the truth. We are also told in 1 Corinthians 16:13 to stand firm in our faith. Faith comes by hearing the truth (The word of God) and we know that Jesus is the truth John 14:6.
So, when we stand firm in the truth, we are guarded against temptation as well as remaining in Jesus who is the truth.
We are told in the beginning of this section of Eph 6:11 to put on the whole armor of God that we may be able to stand against the schemes of the evil one and in v12 because our battle is not against flesh and blood, but against powers and principalities, just as Jesus was in the wilderness.
Therefore, we can see some reasons why it is important for us to put on the belt of truth so that we can stand firm in that truth and combat the enemy when he comes with lies to deceive us.
As well as this, it is important that we stand firm in truth daily when speaking to others. Ephesians 4:25 and to be ready to speak truth to those who ask us about the Lord.
There are perhaps many other reasons you could come up with, but these are just a few mentioned to consider as to why we should put on the belt of truth daily.