Pater veretur ne mora longa infantibus obsit.

Because vereor, vereri, veritus sum is a deponent verb.

Deponent verbs:

• have passive forms
• but active meanings

So veretur is grammatically a passive-looking form, but it means he fears or he is afraid, not he is feared.

Here:

• pater = the father
• veretur = fears / is afraid

So pater veretur means the father fears.

After verbs of fearing, Latin uses ne and ut in a way that often feels reversed to English speakers.

With a verb of fearing:

• ne = that something may happen, when the speaker fears that it will happen
• ut = that not, when the speaker fears that something will not happen

So in this sentence:

• veretur ne mora longa infantibus obsit
• literally: he fears lest a long delay may harm the children
• natural English: he fears that a long delay may harm the children

So ne here does not simply mean ordinary negation. It introduces the thing feared.

Because it is in a fear clause after veretur.

Latin normally uses the subjunctive in subordinate clauses after verbs of fearing:

• timeo ne...
• vereor ne...
• metuo ne...

So obsit is subjunctive because it is the verb inside the clause introduced by ne.

More specifically:

• obsit = present subjunctive
• from obsum, obesse, obfui = to be harmful to

The subjunctive here does not necessarily make the action unreal; it is just the normal construction after a verb of fearing.

obsit comes from obsum, meaning to be harmful to or to hurt.

This verb is built from:

• ob-
  • sum

Its present subjunctive forms are:

• obsim
• obsis
• obsit
• obsimus
• obsitis
• obsint

So obsit means may harm, may be harmful, or might hurt.

This is a good verb to memorize separately, because compounds of sum often have forms that look a little unusual at first.

Because obsum takes the dative of the person or thing affected.

So:

• obsum alicui = I am harmful to someone
• infantibus = to the children / infants

In this sentence:

• mora longa is the thing doing the harm
• infantibus are the ones affected by it

So infantibus is dative because Latin says literally:

• a long delay may be harmful to the children

Yes, mora longa is the subject of obsit.

Breakdown:

• mora = delay
• longa = long, agreeing with mora
• both are nominative singular feminine

Since obsit means may be harmful, something has to be the thing that is harmful. That thing is mora longa.

So the structure is:

• Pater veretur = The father fears
• ne mora longa infantibus obsit = that a long delay may harm the children

Because longa agrees with mora, which is nominative singular feminine here.

Agreement in Latin means an adjective matches its noun in:

• gender
• number
• case

So:

• mora = nominative singular feminine
• longa = nominative singular feminine

If it were longam, that would be accusative singular feminine, which would not fit the syntax here.

• veretur is present indicative
• obsit is present subjunctive

So the sentence presents the father’s fear as a present situation:

• the father fears

And the feared action is also presented in present time relative to that fear:

• that a long delay may harm the children

A very literal sense is:

• The father is afraid that a long delay may be harmful to the children.

Yes, Latin word order is much freer than English word order because the endings show the grammar.

This sentence puts:

• Pater first, introducing the topic
• veretur next, giving the main action
• then the whole fear clause
• with obsit at the end, which is a very common place for a verb in Latin

Latin often likes to place the main verb or subordinate verb at the end of its clause. So infantibus obsit feels very natural.

Other arrangements are possible, for example:

• Pater ne mora longa infantibus obsit veretur
• Pater veretur ne infantibus mora longa obsit

But the original order is clear and idiomatic.

In a broad sense, yes, English may translate the dative in different ways depending on what sounds natural. But grammatically here it is the dative with obsum, so the core idea is:

• harmful to the children

English might express this as:

• harm the children
• be harmful to the children
• be bad for the children

So for the children could appear in a smooth translation, but the underlying Latin construction is specifically dative after obsum.

A very literal unpacking would be:

• Pater = the father
• veretur = fears
• ne = that / lest
• mora longa = a long delay
• infantibus = to the children
• obsit = may be harmful

So, word for word:

• The father fears that a long delay may be harmful to the children.

Or even more literally:

• The father fears lest a long delay be harmful to the children.

That kind of literal version helps show the grammar, even if a more natural English translation would sound smoother.