Matthew 26:38-41
38Then he said to them, "My soul is overwhelmed with sorrow to the point of death. Stay here and keep watch with me." 39Going a little farther, he fell with his face to the ground and prayed, "My Father, if it is possible, may this cup be taken from me. Yet not as I will, but as you will." 40Then he returned to his disciples and found them sleeping. "Could you men not keep watch with me for one hour?" he asked Peter. 41"Watch and pray so that you will not fall into temptation. The spirit is willing, but the body is weak."
Luke 18:1-8
1Then Jesus told his disciples a parable to show them that they should always pray and not give up. 2He said: "In a certain town there was a judge who neither feared God nor cared about men. 3And there was a widow in that town who kept coming to him with the plea, 'Grant me justice against my adversary.' 4"For some time he refused. But finally he said to himself, 'Even though I don't fear God or care about men, 5yet because this widow keeps bothering me, I will see that she gets justice, so that she won't eventually wear me out with her coming!' 6And the Lord said, "Listen to what the unjust judge says. 7And will not God bring about justice for his chosen ones, who cry out to him day and night? Will he keep putting them off? 8I tell you, he will see that they get justice, and quickly. However, when the Son of Man comes, will he find faith on the earth?"
John 14:13,14
13And I will do whatever you ask in my name, so that the Son may bring glory to the Father. 14You may ask me for anything in my name, and I will do it.
Ephesians 6:18
18And pray in the Spirit on all occasions with all kinds of prayers and requests. With this in mind, be alert and always keep on praying for all the saints.