Seems like a simple question, and you might assume the answer is obvious, but sadly, you would be wrong about that.
I asked that exact question on social media and the responses I received were along the lines of:
"Mountains can't be moved even though He said they could."
And I have been fielding those sorts of responses for years now. Every time I suggest that we who follow Jesus should actually follow Him, and put His words into practice - or even that we CAN do these things - I am constantly told that we simply cannot.
I've been through a lot of this kind of thinking the last few years and I'm at the place where I can see that Jesus does empower us to do everything He asks us to do.
That's why He can say, "Why do you call me 'Lord, Lord' and do not do what I say?"
Because if we are in Him, then we can! Otherwise, Jesus is just messing with us, and I don't believe that's what's going on at all.
I think our problem is that Christians today need to move from a Romans 7 mentality into the Romans 8 reality.
Romans 7 is where Paul goes on and on about how the good he wants to do he cannot do and the evil he doesn't want to do he ends up doing anyway. Many Christians live in that chapter and never move on from there.
But Romans 7 ends with Paul asking a question:
"What a wretched man I am! Who will rescue me from this body that is subject to death?"
See, Paul knows that we are all likely to focus on our weakness and less likely to embrace our ability to actually obey Jesus the way He asks us to. So, that's why he gave us Chapter 7 of Romans to sort of get that all out in the open and let it sit there for all of us to see.
"Therefore, there is now no condemnation for those who are in Christ Jesus, because through Christ Jesus the law of the Spirit who gives life has set you free from the law of sin and death."
Paul then goes on in Romans 8 to talk about how we are now living "according to the Spirit" and not according to the flesh.
"You, however, are not in the realm of the flesh but are in the realm of the Spirit, if indeed the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, they do not belong to Christ." - Romans 8:9
"For the grace of God has appeared that offers salvation to all people. It teaches us to say “No” to ungodliness and worldly passions, and to live self-controlled, upright and godly lives IN THIS PRESENT AGE, while we wait for the blessed hope—the appearing of the glory of our great God and Savior, Jesus Christ, " - Titus 2:11-13
"His divine power has given us EVERYTHING WE NEED for a godly life through our knowledge of him who called us by his own glory and goodness. Through these he has given us his very great and precious promises, so that through them you may participate in the divine nature, having escaped the corruption in the world caused by evil desires." 2 Peter 1:3-4
And of course,
And my fave:
Do we fall down? Yes. But so do little children learning to walk. No parent says, "Well, he'll never walk, I guess. He just keeps falling down. I guess I'll stick him in this walker forever."
We shouldn't do this to ourselves, either.
More and more we learn to walk in Christ, and we learn to stand more than we fall over time.
It's not about us trying harder. In our strength we know we can do nothing. But we also know that if we abide in Him and if He abides in us, then we will "bear much fruit" and that fruit is the working of the power of the Holy Spirit within us who empowers us to live like Christ in this present age.
It really is about daily resting in Him and learning to abide in Christ.