I’ve mentioned this before, but the command to love the is Lord unique among all the world’s religions, and especially so in the time Moses is imploring the people of Israel to do so. The first verse:
Love the Lord your God and keep his requirements, his decrees, his laws and his commands always.
Why does love precede obedience? Because God is not an abstraction; he is not an idea or an abstraction. And because we now know God is a Triune God of love, it makes perfect sense that our obedience to him would have to also flow out of love.
And for the Israelites Moses is putting before them something we know is humanly impossible, which is perfect obedience as requirement for blessing. We know that’s not true even in the OT, but a relationship without holy God requires it nonetheless. He says in v 26-28:
26 See, I am setting before you today a blessing and a curse— 27 the blessing if you obey the commands of the Lord your God that I am giving you today; 28 the curse if you disobey the commands of the Lord your God and turn from the way that I command you today by following other gods, which you have not known.
This points to Christ because cursed is anyone hung on a tree, as we learn later in Deuteronomy 21:23. The curse we deserve because we cannot obey perfectly, Christ took for us so God might bless us because of his obedience. Really amazing when you think about it, and God had to go through all of this to eventually convince us he himself would be our blessing.
And the command to love God is also impossible if God is our judge. This is what Martin Luther experience before his conversion when he said he literally hated God because God was his judge and he knew he could never please him. But because he is no longer our judge but our savior, we can truly love him out of the overflow of gratitude in our hearts.