God is an expert series: You are an expert that:
1 - Every science in the world has an expert. There is an expert in engineering, there is an expert in ophthalmology, there is an expert who appraises furniture and antiques, and so on. Even psychology has experts.
2 - God - the Almighty - in the Qur’an, His name, The Expert, is not mentioned except in the human soul from the inside before the outside, as if it were a clear mirror before the eyes of God, and He wants you, as a believer, to clear your view of things as well, so look with the eyes of God - the Almighty - and God is Most High and Most Knowing.
Allah says
يَا أَيُّهَا الَّذِينَ آمَنُوا إِذَا ضَرَبْتُمْ فِي سَبِيلِ اللَّهِ فَتَبَيَّنُوا وَلَا تَقُولُوا لِمَنْ أَلْقَىٰ إِلَيْكُمُ السَّلَامَ لَسْتَ مُؤْمِنًا تَبْتَغُونَ عَرَضَ الْحَيَاةِ الدُّنْيَا فَعِندَ اللَّهِ مَغَانِمُ كَثِيرَةٌ ۚ كَذَٰلِكَ كُنتُم مِّن قَبْلُ فَمَنَّ اللَّهُ عَلَيْكُمْ فَتَبَيَّنُوا ۚ إِنَّ اللَّهَ كَانَ بِمَا تَعْمَلُونَ خَبِيرًا (94) النساء
O you who have believed, when you travel in the path of God, so, find out, And do not say to the one who greets you, “You are not a believer, you seek the reward of the life of this world, God has many spoils, This is how you were before, so God has bestow you, so find out. Indeed, Allah is ever Aware of what you do. (94) An-Nisa
We benefit from the noble verse as the follows:
1 - The speech states that God - the Almighty - is Expert and specifically addresses those who believe in Him.
2 - Telling the believers that while they are moving around the earth while they believe in God - the Almighty - and they see their brothers who may be new to the religion, or have less faith than them, He tells them to (find out) before they utter a word, just a word, that the one in front of you is not a believer, so he says to them: the reason for this is that God is an expert of what is going on in their selves: seeking one of the spoils of the world, such as pulling the carpet from under your feet in front of you, as they say, such as taking your religious status or being better than you, or taking from you a job you dreamed of, or a bride, or something else. From the spoils of the world because of the good things in it, which you may not have.
3 - He does not leave you after warning (find out) until he reassures you that your provision is essentially from God, and God has many spoils.
4 - He reminds you that you were once (a new Muslim, or at the very least: a believer of little faith), so remember.
5 - So, find out... for the second time in the same verse, why? Because God is expert of what is going on in your self, you will not deviate from it.