Why, when we pray, should we close the prayer with, "In Jesus name, amen"?
The word "amen" is a transliterated word from the Hebrew language. Wilson's Old Testament Word Studies defines it as meaning, "Let it be granted, let it be done, and unalterably confirmed." It can be seen in Numbers 5:22 where a curse is pronounced on a woman if she had committed adultery. "Then the woman shall say, 'Amen, so be it.'" In saying this the woman is accepting the consequences of the curse if it is found out that she had been committing adultery.
At the end of a prayer, it is a statement that the one praying is firmly asking that his prayer be granted. If someone else is leading a prayer, those listening often will say "amen" as well to indicate their agreement: “This is true, or may it come to pass, or may it be fulfilled.” An example is found in I Chronicles 16:35-36, "And say, "Save us, O God of our salvation; Gather us together, and deliver us from the Gentiles, To give thanks to Your holy name, To triumph in Your praise." Blessed be the LORD God of Israel From everlasting to everlasting! And all the people said, "Amen!" and praised the LORD." Paul implies that saying "amen" at the end of a prayer was expected in Christian worship. "What is the conclusion then? I will pray with the spirit, and I will also pray with the understanding. I will sing with the spirit, and I will also sing with the understanding. Otherwise, if you bless with the spirit, how will he who occupies the place of the uninformed say "Amen" at your giving of thanks, since he does not understand what you say?" (I Corinthians 14:15-16).
The phrase "in Jesus' name" means that the requests being made are done in accordance with Jesus' will or by his authority. We still do this today when you sign a check or bank card transaction. By signing your name, you are giving the possessor the authority to withdraw the amount from your account. Thus the transaction is being done in your name, even though you don't have to stand there personally to do it.
"And in that day you will ask Me nothing. Most assuredly, I say to you, whatever you ask the Father in My name He will give you. Until now you have asked nothing in My name. Ask, and you will receive, that your joy may be full" (John 16:23-24).
This doesn't mean we can ask for anything we imagine and Jesus will give it to us. He is saying that anything we ask that is according to his desires will be granted. Jesus is giving us the authority to come before God and make our desires known. It isn't a blank check, but when our requests conform to Jesus' will, Jesus promises to answer them. "And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks to God the Father through Him" (Colossians 3:17).
Thank you so much for your reply. You answered my question very well and I understand now.