Jesus quoted this verse.
Mark 12:28-30 "Then one of the scribes came, and having heard them reasoning together, perceiving that He had answered them well, asked Him, 'Which is the first commandment of all?' Jesus answered him, 'The first of all the commandments is: Hear, O Israel, the Lord our God, the Lord is one. And you shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength. This is the first commandment...'"
We must first know God before we can love Him. We must first know God before we can worship Him. How can we walk with God at a distance?
My wrestling the past couple months have been particularly been around the implications raised by these verses. I can sum up the wrestling with this verse: "Teach me to do the thing that pleaseth Thee - for Thou art my God" (Psalm 143). In the past, I wanted to do "the thing that pleases God" because it was right; but now I'm beginning to have a deeper motivation. I want to do "the thing that pleases God" because He is my God. I want to know God, to enjoy fellowship with Him, to spend time together with Him both privately and in public worship, to find out who He is, to find out what things please Him and what things offend Him, to taste eternal life and to fulfill the purpose of my life. The first step is to hear His words and take Him at His word - believing what He says - and basing all else upon that.