This fact base on my understanding and likewise i will say it is spiritual as well.
Sometimes ago RCCG started a 100 Days Prayer and Fasting in with about 115 prayer point in which Prayer point 50 - 91 was dedicated to the Nation (Nigeria). And Now its God's time to answer the prayer and he Chooses Pastor Osinbajo.

But you may say other people are available for God to Chose, Nay the bible say:

The husbandman that laboureth must be first partaker of the fruits - 2 Tim 2:6

RCCG had labour for the country, carrying the burden of the nation (as well as Pst Osinbajo), therefore, they are worrthy of it.

One might as well say, why him not any other person in Church. The answer is simple, God know Joseph will become PM in Egypt that is why he was allow to be sold to egypt. God allow Pst Osinbajo to sojourn in APC so that he can accomplished the will of God.

Some Men of God and GOCs Knew this but will not voice out so as to prevent accusations for politicians

Last Question a PDP/GEJ supporter will ask is why will God Chooses APC/Buhari Bokoharam(as many will say)?
I will answer that when am back from church in this same tread - Remain Blessed and Well Favoured

Goodmuyis

Ref:
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https://trccg.org/rccg/2014-one-hundred-days-fast/

Reserved for A book

God will reward u.