Mark 11:23 For assuredly, I say to you, whoever says to this mountain, ‘Be removed and be cast into the sea,’ and does not doubt in his heart, but believes that those things he says will be done, he will have whatever he says.

Did you see that it is whosoever, not those who have been in the Lord for a very long time? Sometime, we feel God won't answer us because we are not righteous, forgetting that we have been made God's righteousness. Whosoever means anyone who have faith in God through Christ Jesus can speak to any mountain.

I Samuel 17:45 Then David said to the Philistine, “You come to me with a sword, with a spear, and with a javelin. But I come to you in the name of the Lord of hosts, the God of the armies of Israel, whom you have defied. 46 This day the Lord will deliver you into my hand, and I will strike you and take your head from you. And this day I will give the carcasses of the camp of the Philistines to the birds of the air and the wild beasts of the earth, that all the earth may know that there is a God in Israel.

David did not have any sword when he made a confession of cutting off the head of Goliath, but he used the sword of the spirit which is the word of his mouth. Words are very powerful, especially, the word (rhema) from God's word. What David spoke was revealed word from his meditation. How did I know? He called the Israel's armies, God's armies and of circumcision. He called Goliath an uncircumcised gentile.

Your confession becomes powerful when you speak from your position in Christ Jesus and not as an ordinary man. Know that your words carries power and you are mindful of what you say. Don't be cursing people all in the name of play and jokes, angels won't take you seriously again. Become mindful of who you are and speak to that family plague and poverty. Speak and curse that sickness and disease in your body.