[Avodah] vehagita

[Eli Turkel]

ShA, YD 246:1 (in fact, the very 1st seef of Hilchos Talmud Torah)
 in the Rema:
"UBESHAAS HADECHAK afilu lo kara rak KS shachris ve'arvis 'lo yomishu
mipicho' korinen lei..">>

Let us go back to the original source.
The Gemara in Nedarim 8a says that someone who swears not to learn
a mishna is required to keep the neder and it is not considered "mushba
ve-omed me-har sinai" because one is only required to say kriat shema.

The rishonim struggle with this gemara. The Ran explains that talmud torah
all day is a mitzva. However "mushba ve-omed me-har sinai" only applies to
mitzvot explicit in the Torah. The Radvaz (3:416) disagrees and brings many
rishonim including Rabbenu Yona and Rosh & Rashba who state that Talmud Torah
beyond Kriat Shema is "reshut".

So according to these rishonim learning beyond Kriyat Shema is a mitzvat Aseh
and one should certainly do whatever possible but there is no din of ve-hagita
beyond kriyat shema

The Steipler (Berachot) (no left wing radical) comes up with a major
chiddush that for Charity (or gemillat chesed) one who is unable to
give is not "anus" but is "not chayav"
since tzeddaka has no minimum but is only a percentage.
Similarly one who is busy with making a living or other mitzvot is not "anus"
but is "not chayav". Hence, he explains why the gemara gives rules when one
can stop learning and do a mitzvah rather than just applying the rule
"ha-osek be-mitzvah patur me-hamitzvah". Since the minimum is only kriat shema
once one does a mitzvah instead (under the conditions allowed) he is simply
not chayav at that time in talmud Torah.

Hence, according to all these shitot learning Torah applies only when one
is not occupied with other necessities. The Ramah is saying that these
necessities
should not take up the entire day except beshaat hadchak. Even in the
case of other responsibilities one is required to have set hours for
learning and
not rely on the kriyat shema.

see also bet halevi Shemot 24:7 for a discussion of the mitzvat aseh to learn

-- 
Eli Turkel