I probably should say at this point that I am not putting myself out as a a gospel authority or scriptorian. Far, far from it. I'm just a woman digging into the word of God and seeing what I can learn.
3. Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ:I am glad that the 3rd verse opens up with several of the same words as the 2nd verse ended; it makes things easier from a memorization standpoint. ("Blessed be the God and Father of our Lord Jesus Christ" - Eph 1:3; "from God our Father and from the Lord Jesus Christ" - Eph 1:2). We humans are a rather thick-headed bunch and time and the repetition helps to perfect whatever it is we are trying to learn, whether it be an intellectual pursuit, a sport, an artistic performance, etc.
I see Paul's use of the phrase, "Blessed be the God....", as his acknowledge of God's exalted status. This puts me in mind of the hubbub created back in the 1980's when Nancy Reagan went to England for the marriage of Charles and Diana and the news that when she met the Queen, she would not curtsey. I guess that ticked off a lot of English folks. But I would have done the same thing. (Oops, there goes my invitation to tea - and I'm a serious Anglophile.) A person not living in a monarchy does not follow some of the social rules particular to that system of government. But we are all children of God.
And, luckily for us, our Heavenly Father has given us "all spiritual blessings"; He has given us everything we need (which is not the same as everything we want). We only have to talk to a soldier or a first responder to know how important it is to have everything we need when we go out on patrol. Why does He do it? Because He loves us and because Christ "took the bullet" that had our name(s) on it.
4. According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:Even before the world was made God chose us for His own. How cool is that? Before the light was separated from the darkness, God knew us and loved us, each and every person that has ever been born. We all have the agency, the power to choose paths that will change our lives, for good or bad. He knew not everyone would consistently make the righteous choice, but He gave us that freedom. I cannot imagine the faith and trust that took. He wanted (and wants) every one of us to return to Him; in order to do that we have to be 'holy and without blame', as no unclean thing can live in God's presence.
For which spiritual blessing are you most grateful this week?