Deuteronomy 6:4-5 NASB

"Hear, O Israel!  The LORD is our God, the LORD is one!  And you shall love the LORD your God with all your heart and with all your soul and with all your might."

Without a doubt, this calling to "all" is a major theme in the book of Deuteronomy, and is affirmed by Jesus as "The greatest commandment".  In other words, when it came to the commandments, this was overall, without which there would be no keeping of any of the commandments of God because God knew that obedience was not a matter of the will alone, but a matter of the heart and soul:  Oh, that [this people] had such a heart in them, that they would fear Me, and keep all My commandments always," (Deut. 5:29).  This call of God was huge, running like the Amazon River through the whole book of Deuteronomy:

• "You shall walk in all the way which the LORD your God has commanded you, that you may live," (5:33).
• "keep all His statutes and His commandments, which I command you, all the days of your life," (6:2).
• "And you shall do what is right and good in the sight of the LORD, that it may be well with you," (6:18).
• "Therefore, you shall keep the commandments of the LORD your God to walk in His ways and to fear Him," (8:6).
• "And now, Israel, what does the LORD your God require from you, but to fear the LORD your God, to walk in all His ways and love Him, and to serve the LORD your God with all your heart and with all your soul," (10:12).
• "You shall therefore love the Lord your God, and always keep His charge, His statutes, His ordinances, and His commandments," (11:1)
• "And it shall come about, if you listen obediently to my commandments which I am commanding you today, to love the LORD your God, and to serve Him with all your heart and all your soul, that He will give the rain for your land in its season," (11:13-14).
• "For if you are careful to keep all this commandment which I am commanding you, to do it, to love the LORD your God, to walk in all His ways and hold fast to Him; then the LORD will drive out all these nations from before you..." (11:22-23).
• "the LORD your God is testing you to find out if you love the LORD your God with all your heart and with all your soul.  You shall follow the LORD your God and fear Him; and you shall keep His commandments, listen to His voice, serve Him, and cling to Him," (13:3-4).
• "obey (lit., "listen to His voice") Him with all your heart and soul..." (30:2)
• Moreover the LORD your God will circumcise your heart and the heart of your descendants, to love the LORD your God with all your heart and with all your soul, in order that you may live," (30:6).
• "turn to the LORD your God with all your heart and soul," (30:10).
• "So choose life in order that you may live, you and your descendants, by loving the LORD your God, by obeying His voice, and by holding fast to Him," (30:19-20).

The call of God, as in any marriage relationship, is to 100% faithfulness, love and purity.  If in pre-marital counseling, one baulked at this high calling, the best counsel to the other would be "Run!"  Marriage has a right to demand 100% and, in fact, it necessitates 100% to not only be healthy, but survive. Anything less is a farce and we all know it.  How can we expect anything less than this in our relationship with God?  He doesn't!  Is this a yoke too hard to bear?  Ask someone who is in love.  They would laugh at anything less. To this person, this calling is the joy, delight and expectancy that gives meaning, dignity and hope to the relationship.  God raises the level of "this holy relationship" to "All!"  Who wouldn't want that?