Rashi on Numbers 7:20/רש"י על במדבר ז׳:כ׳

1כף) כף אחת also denotes “hand”) — in allusion to the Torah that was given from the hand of the Holy One, blessed be He (Numbers Rabbah 13:16).

2עשרה זהב — TEN SHEKELS, GOLD — corresponding to the Ten Commandments (Numbers Rabbah 13:16).

3מלאה קטרת — The total of the word קטרת according to their numerical value is 613, the number of the Biblical commandments, except that you must exchange the קו"ף by דל"ת, according to the “Method of Permutation” known as א׳׳ת ב"ש ג"ר ד"ק (by which the first letter of the Alphabet may take the place of the last, the second that of the one before last etc.) (Numbers Rabbah 13:16).