The writer of Hebrews quoted Psalm 40:7,8 in Hebrews 10:5-7. While Psalm 40:7,8 refers initially to David's desire to do God's will, the writer of Hebrews under the inspiration of the Holy Spirit saw it as a prophecy concerning Christ's desire to fulfill God's will as the Sacrifice for the sin of humanity. Believers can use David's and Christ's willingness to do God's will as an example of how they can be obedient to God.
HOW CAN I KNOW GOD'S WILL FOR MY LIFE?
WHAT ARE SOME SPECIFICS OF GOD'S WILL FOR ME THAT ARE RECORDED IN HIS WORD?
HOW CAN I OPEN MY EARS TO HEAR GOD'S WILL?
AFTER I'VE DISCOVERED GOD'S WILL, HOW CAN I BE FAITHFUL IN OBEYING HIS WILL?
Romans 12:1
Some key points:
Present your bodies a living sacrifice to God.
Make the body holy.
Make self acceptable to God
Render reasonable service
Be not conformed to the world
Be transformed from the world
Many Christians depend exclusively on their impressions to determine the will of God.
However not all impressions are valid; some are from God; some are from satan; some are probably of our own making.
Since it is difficult to determine the origin of an impression, we can easily make a mistake while assuming that a feeling is sent from God.
Our Lord has promised to enlighten us and "guide us with His eye". On the other hand, He wants us to "test" our impressions and leadings.
Therefore, every impression should be tested by 4 criteria before being accepted as valid:
Is it scriptural?
Is it right?
Is it providential? Circumstances, are the necessary doors opening or closing? Is the Lord speaking to me through events?
Is it reasonable?
EPHESIANS 6:6-7 Not with eyeservice, as menpleasers; but as the servants of Christ, doing the will of God from the heart. With good will doing service, as to the Lord, and not to men.