In surat an-Nisaa' we read (4:3):
And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hand possesses. That is more suitable that you may not incline [to injustice].
It seems as if there's something missing here the verse jumps from the fear for being unjust to orphan girls -which was also discussed earlier in the surah- to marrying up to four women. I wonder what this missing information is!
One also may notice that much later in the same surah we may find a resumption of the topic of orphan girls this time in context of marrying them (I'm unclear whether there's a link between both verses):
And they request from you, [O Muhammad], a [legal] ruling concerning women. Say, " Allah gives you a ruling about them and [about] what has been recited to you in the Book concerning the orphan girls to whom you do not give what is decreed for them - and [yet] you desire to marry them - and concerning the oppressed among children and that you maintain for orphans [their rights] in justice." And whatever you do of good - indeed, Allah is ever Knowing of it. (4:127)
My question is:
What is the link between marrying up to four women/girls and fearing to deal unjustly with orphan girls?