Matt 4:1-4 Then Jesus was led by the Spirit into the desert to be tempted by the devil. After fasting forty days and forty nights, he was hungry. The tempter came to him and said, “If you are the Son of God, tell these stones to become bread.” Jesus answered, “It is written: 'Man does not live on bread alone, but on every word that comes from the mouth of God."
I've been thinking a lot about this scripture lately because, shall I say, I'm butting heads with a person preaching on Youtube that won't take into account the commandments of the Old Testament. Jesus knew the Old testament very well. In fact, he used it as his armor against the devil. He answered the devil's temptation by quoting part of Deut. 8:3 'He humbled you, causing you to hunger and then feeding you with manna, which neither you nor your fathers had known, to teach you that man does not live on bread alone but on every word that comes from the mouth of the Lord.'
Every word means every word. So just how does this fellow, who preaches the gospel only, protect himself when the devil comes along to tempt him? I dunno, because he doesn't accept the ten commandments. If you don't accept the Old Testament, then it stands to reason that you don't accept the Ten Commandments. And if you don't accept those, you are going to be sinning right and left. And how is that following Jesus? Satan is the author of all sins, not Jesus, and if you love your sins, then you're following satan. No, we can't be perfect. No one is perfect, and everyone is going to stumble. That's why we rely on His mercy, His merits.
Ephesians 6:10-11 “Finally, grow strong in the Lord, with the strength of his power. Put on the full armor of God so as to be able to resist the devil's tactics." His tactics are clear and evident---to take as many of us down with him as he can.
If Jesus used scripture as His armor against the devil, so should we. 1 Peter 5:8 Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour.