These verbs can appear to be complex because if you analyze the words, you will see that they can be broken down into a prefix, “for”, and each of the verbs that they derived from (or stems), “bid”, “get”, “give”, “go”, “swear”. All of these verbs have a specific meaning, but with “for” added to the front of the words, they have different meanings. Therefore, it can be argued that these original verbs are stems to all of the derived words within this paradigm.
These verbs can also appear to be simplex because although “bid”, “get”, “give”, “go”, and “swear” are all verbs with a particular meaning, if “for” was a prefix in this paradigm then the affix would have a parallel meaning throughout all of these words. For example, adding the suffix “-ed” to any verb creates a word form of the lexeme which represents that the action has happened in the past.
I think that the words in this paradigm are simplex because despite the fact that it seems they all share a prefix, the ‘prefix’ does not have the same meaning in each word. For example, if you compare 1)”give” and “forgive” to 2)”bid” and “forbid”, you will see that adding “for” to “give” changes the meaning from “to present voluntarily and without expecting compensation; bestow” to “to grant pardon for or remission of; absolve”. Whereas, adding “for” to “bid” changes the meaning from “to command; order; direct” to “to command (a person) to not do something, have something, etc.” In comparing these two examples you will see that adding “for” to each of the ‘stems’ does not create the same change. Therefore these word forms are not systematically related to their original lexemes. So I feel that it is safe to assume that “for”, in this given set of words, is not a morphological constituent.