Reference for Moed Katan 7:2
ר' ישמעאל אומר מה חריש רשות אף קציר רשות יצא קציר העומר שהיא מצוה
so is the reaping [here mentioned] optional reaping; outside this [law] is the reaping [of the new barley] for the 'omer'<span class="x" onmousemove="('comment',' 'The sheaf of the first fruit of your (barley) harvest'. V. Lev. XXIII, 10ff. R. Ishmael holds that this may be reaped even on Sabbath. R. Ishmael's statement is for the moment irrelevant, though it comes in later. R. Akiba's dictum shows that the extension, i.e., the pre-sabbatical bar on tillage, is not merely a pristine halachah-usage, but has textual basis.');"><sup>3</sup></span> which is a religious duty [by ordinance]!<span class="x" onmousemove="('comment',' Cf. M. Sheb. I, 4 and Mak., Sonc. ed. p. 48.');"><sup>4</sup></span>