Why not make it a point to study all the things the Lord says in His Word about 'ol slewfoot still being around and active today?
Here's one to consider that shows the devil is still around today and is very much active:
2 Corinthians 4:3,4
But if our gospel be hid, it is hid to them that are lost:
In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
Here's a few more...
1 Peter 5:8-9
Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour.
Resist him, standing firm in the faith, because you know that the family of believers throughout the world is undergoing the same kind of sufferings.
Romans 16:20
The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you.
1 Corinthians 7:5
Do not deprive each other except perhaps by mutual consent and for a time, so that you may devote yourselves to prayer. Then come together again so that Satan will not tempt you because of your lack of self-control.
James 4:7
Submit yourselves, then, to God. Resist the devil, and he will flee from you.
John 10:10
The thief comes only to steal and kill and destroy; I have come that they may have life, and have it to the full.
1 John 3:8
The one who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil’s work.
To do that is to consider living people that had a hold of these letters back then. A promise to those whom were called Saints at Rome, and also the Gentiles, where being wrote to in that day in age. Using the bible without accurately pointing out, for example, (1 Thessalonians, was written to believers in that congregation in that day.)
Though we could argue whether or not Satan is alive or active today, depends on what you believe anyway... which personal and I have no idea. Revelation from John the beloved stated that he was going to be finished off, and I believe personally today, he has been finished off.