Isaiah 44:3-5 NKJV
For I will pour water on him who is thirsty, and floods on the dry ground; I will pour My Spirit on your descendants, and My blessing on your offspring. They will spring up among the grass like willows by the watercourses.' One will say, 'I am the LORD's'. Another will call himself by the name of Jacob. Another will write with his hand, 'The LORD's,' and name himself by the name of Israel.
God promised Israel that He would pour water on the thirsty. He said He would pour out of His Spirit and blessings on their children. Why should we as Christians expect anything less? The only reasons He would say that to them was because of His love for them and the covenant He had with them through Abraham, Isaac and Jacob. God loves us and has a covenant with us through Jesus Christ.
Galatians 3:26-29 NKJV
For you are all sons of God through faith in Christ Jesus. For as many of you as were baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus. And if you are Christ's, then you are Abraham's seed, and heirs according to the promise.
In addition to being in a covenant relationship, there is another qualification for receiving an outpouring of God's Spirit - thirst. The thirstier we are, the more we can take. God will pour and flood those who want it badly enough. When we go to the water of the Word, the “additive” of the Holy Spirit increases the flow into our spirits. We can get much more out of the Word when we allow the Holy Spirit to participate in it being delivered to us. We do that by being conscious of His presence when we get into the Word, and asking for His help to understand what we read and study.