Why is God being radically selfish most loving?

After a 12 month engagement, months of planning, weeks of anticipation, a morning of preparation – the bride walks the aisle into the joyous arms of her groom.
The hour has come
After years of trying, nine months of joyful, growing discomfort, onies brought and prams purchased the baby cry is heard as she snuggles into her mother’s exhausted arms.
The hour has come
Decades of dreaming and training, endless discipline, countless failed efforts, the medal is draped over her neck and the crowd erupt, only silenced by the notes of the nation’s anthem.
The hour has come
‘Jesus replied. ‘The hour has come for the Son of Man to be glorified.’ (John 12:23)  An event, long anticipated and waited for, laden with weight and purpose and substance is here.  The hour has come.
But what is this hour?
The hour when Jesus dies
It is the moment of Jesus’ death: ‘He said this to show the kind of death he was going to die.’  (John 12:33)
The hour when God is glorified 
But it is also the moment God is glorified.  ‘The hour has come for the Son of Man to be glorified…Father, glorify your name!’ (John 12:23, 28)
Glorified means to show something beautiful and unique, for some reason hidden from us, as it truly is.  It means to magnify.  Not like a microscope (making something smaller brighter and bigger and bolder than it really is) but like a telescope (making something far from us visible by correcting our deficiency).  Like the astronomer who spends most of their time, once they have identified their principal star, adjusting the dial and bringing it ever into sharper and more splendid focus, so John now spends 10 chapters on ‘this hour’ – the moment of Jesus’ death.  Having covered three years in his first 11 chapter he now covers just one week in ten.  He keeps turning the focus dial of his gospel-telescope bringing into ever sharper focus the magnitude of Jesus’ death.
God saves to glorify his name
Notice Jesus emphasises his death is mostly and ultimately about God’s glory: ‘…the Son of Man…glorified…Father, glorify your name!’  Jesus’ death, God’s rescue, our salvation – they are ultimately about God and his glory.  From the Old Testament God’s rescuing has always been about his glory: ‘…he saved them for his name’s sake…’ (Psalm 106:7-8).  It is about his glory across the world, ‘…that the nations might glorify God for his mercy.’ (Romans 15:9)  Even before time began it was his intention: ‘…he predestined us for adoption…to the praise of his glorious grace.’ (Ephesians 1:5-6)
Is this egocentric?  Is this conceited and arrogant by God?  Is it selfish and unloving?
God glorifying his name is love
It would be, unless our joy and God’s glory were interwoven.  Like how a best-man’s joy escalates as the groom is applauded and made much of.  Or how a parents’ delight swells as she can truthfully make much of a child’s achievement.  Or as a husband’s delight is found as he buys gifts for his wife. There is nothing more joyful than seeing and knowing the glory of God.  So for God to be focussed on his own glory IS the greatest love he could show.  Determined to defend his name and promote his glory in the cross leads to our salvation and rescue and joy and redemption.  Saved by the glory of God for the glory of God.
Jesus’ death: the model for our life
Jesus died ultimately to display God’s glory by ‘drawing all people to himself’ and so that ‘the prince of this world will be driven out.’ (John 12:31).  Jesus’ death (to serve and sacrifice for the glory of God and therefore the joy of people) becomes the model of our lives.  To live for the ultimate joy which is God’s glory.  Therefore ‘hating our lives’ (John 12:25) becomes the most self-loving thing we could do.
‘Not to us O Lord, not to us, but to your name be the glory.’ (Psalm 115:1)

‘So whether you eat or drink or whatever you do, do it all to the glory of God.’  (1 Corinthians 10:31)