I see the "God is Sovereign" as a fill in when scriptural or logical argument cannot be made.
The "God is Sovereign" argument seems to me to be that you cannot stand on various scriptural promises because you are viewed as putting God in a box out of selfish motives and God is Sovereign.
On one hand, God limits his own options (Sovereignty?) by His Word and His personal directives to each of us. On the other hand, the only way we know God's will is through His Word and His directives.
Frequently when God directs men to do something, it does not get done. For example, Jesus taught us to pray that "God's Will be done on Earth as it is in Heaven". Under "God is Sovereign" it would be done - because it is God's will - Jesus would not command us to pray for something that was not His will.
Honestly? Calvinists just add God's sovreignty into everything because God is soveriegn.
Tell me, is your sanctification complete? Or do you still struggle a lot with your sins?
God's completely sovreign and God could sanctify you with one word. With one word all of this pain,suffering,poverty ...etc would be over. God is powerful enough to do it. Or to do anything that would catch his tiniest whim.
However just because all of this doesn't happen doesnt mean that God isn't sovereign over all. These things are just not in God's will right now in this current second of time.
Using Jesus's sermon on the mount is kind of a weak argument. In the sermon on the mount God was teaching sections on how to pray it wasn't one strict prayer. I'll break it down with what Christ was teaching
Our Father who art in Heaven - always start your prayers addressing God as Father
Hallowed be your name - Acknowledge that your Lord God is Holy,Perfect, who is wise and just. Look at how perfectly the angels sing to their ruler and King to get an idea.
Your kingdom come your will be done. - Pray about the upcoming kingdom and for God's will to be done not yours.
on earth as it is in heaven. - easy needs no explanation.
Give us this day our daily bread - repeat of last. As we're working for God God gives us places and people to work with.
Forgive us our debts as we forgive our debtors - ask Gid to forgive us.
And lead us not into temptation - plead with God to help you with the many temptations you have.
But deliver us from the evil one - self explanatory.
For thine is your honor,glory,and power forever and ever amen - again see how angels sing for reference.
At least 3 times Jesus said to acknowledge God's sovreignty in your prayers.
While not every christian doesn't pray this way right now at this second of their life doesnt mean as they're drawing closer to their final sanctification that they won't. There are sins i commit today that i didnt 6 months ago and there are sins I committed my whole life thwt I NEVER partake again.
Should Christians pray in the lines that Jess taught us to. Yes. But every Christian grows at completely different rates. Just because they don't lray that way today doesnt mean they won't in 10 years. And when they do start to pray that way it only PROVES God's sovreignty and plan.