“My heart is steadfast, O God, my heart is steadfast; I will sing and give praise.”
You can see the evidence when one has idols in their lives. Idols can be anything or anyone - sometimes our own selves.
Jesus was the perfect example on how He did not allow any idols to get in His way to the cross.
When your heart is fixed on God, then all your decisions, thoughts and reactions will be based on His approval.
He is a jealous God who is madly in love with you, and know that putting him first in your life; you will have great success.
Love Him the way He wants to be loved.