2 Samuel 7:27 NKJV
For You, O Lord of hosts, God of Israel, have revealed this to your servant, saying, ‘I will build you a house.’ Therefore Your servant has found it in his heart to pray this prayer to You.
1 John 5:14-15 NKJV
Now this is the confidence that we have in Him, that if we ask anything according to His will He hears us. And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him.
The main difference between the Old and New Testament is the things that were fulfilled in Jesus Christ. Other than that, almost everything is the same. Keep in mind that Jesus only had the Old Testament when He walked the earth and the first disciples and apostles only had the Old Testament as well. The first members of the church of Jesus Christ also had His words but the official New Testament was not available until years after Paul and others evangelized the world. It took Peter having an encounter with God to get him to understand that the separation between Jews and Gentiles was no longer valid under the New Covenant. Christian Jews had to get a revelation that the non-Jewish believers were not required to abide by Jewish rules and culture recorded in the Old Testament in order to be saved. The Old Testament was all they had. So most of what we find in the New Testament can be matched with the old. One example is principles of prayer. There are different kinds of prayer. The type of prayer we are looking at today is the prayer of petition (asking for something). In 2 Samuel 7, we see David praying to God about his house and his posterity. He tells God that he had the courage to make his request in prayer because of what God had already told Him. In 1 John 5:14-15, the apostle John says that our confidence in prayer to God is based on our knowing that what we are asking for is in accordance with His will. Both accounts are revealing the same principle. We cannot have confidence in prayer unless we know God has already said something that indicates our request is acceptable. So let us search the scriptures and know the basis of our right to request something from God before we approach the Throne of Grace in prayer. This will help us pray in faith.