The Aruch HaShulchan (Orach Chayim 53:8) clarifies that the Rema’s discussion of murder is only an example. Any and all sins are subject to the same “intentionally versus unintentionally” distinction the Rema makes.
As far as one who has a pleasant voice, the Aruch HaShulchan (sk 13) lauds this as a special gift that one is granted from G-d. If a shliach tzibbur stands before Him in true heartfelt praise, he will be truly blessed. The Aruch HaShulchan (sk 14) further notes that one who serves as a shliach tzibbur must take care to articulate and pronounce every word properly – each letter and vowel must be correct. This is included in the Gemara’s requirement of someone with vast scriptural proficiency. One with such knowledge will not find the various verses that constitute major portions of our tefillah alien and therefore difficult to pronounce.
(We note, parenthetically, that many communities have different havarot, or pronunciations. Lithuanians, Germans, chassidim, Sephardim, etc. all have different ways of pronouncing Hebrew. Syrian Jews are very careful to pronounce all words mi’le’ra – with the accent on the last syllable. Other communities pronounce words mi’le’eil – with the accent on the opening syllable. Some Jews, like the Yemenites, have the letter thav as opposed to a sav and a jimmel as opposed to a gimmel.)
The Mishnah Berurah (ad loc. sk 13), in understanding the essence of the Gemara, explains that it is proper to seek out a shliach tzibbur who is a tzaddik ben tzaddik – a righteous man who is the son of a righteous man. There is no comparison between the prayer of a tzaddik ben tzaddik and that of a tzaddik ben rasha. (This concept is based on Genesis 25:21, which states that G-d answered “his” – i.e. Yitzhak’s – prayers for a child. Although Rivkah also prayed, her prayers were considered deficient compared to Yitzhak’s since her father was the evil Bethuel.)
Lest one think that it is imperative to seek only someone who possesses impeccable family pedigree to serve as a shliach tzibbur, the Mishnah Berurah notes the Rosh’s comments that the requirements to serve as a shliach tzibbur do not necessarily include family pedigree. If someone is a tzaddik himself but does not come from a distinguished family, he can serve as a shliach tzibbur as long as his father is not wicked.
We may suggest that “wicked” perhaps only means wicked like Bethuel who was a rasha mefursam – whose wicked behavior was on public display. Someone whose improper behavior is not well known might perhaps not be classified as wicked in this context. Consequently, someone who possessed such a father would still be able to be a chazzan according to the Rosh.
(To be continued)