Answer: Anyone who comes to God must believe (1) that He exists, (verse 6). Faith must have an object, and the proper object of genuine faith is God. And anyone who comes to God must believe (2) that He rewards those who earnestly seek Him, (verse 6).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
Jeremiah 29:13: [God said,] "You will seek Me and find Me when you seek Me with all your heart."
Isaiah 61:8: [God said,] "For I, the Lord, love justice; I hate robbery and iniquity. In My faithfulness I will reward them and make an everlasting covenant with them."
Jesus says in Matthew 10:42: "And if anyone gives even a cup of cold water to one of these little ones because he is my disciple, I tell you the Truth, he will certainly not lose his reward."
Revelation 22:12: [Jesus said,] "Behold, I am coming soon! My reward is with Me, and I will give to everyone according to what he has done. I am the Alpha and the Omega, the First and the Last, the Beginning and the End."
