כי תשא This has the meaning of obtaining: WHEN THOU TAKEST [THE SUM], (not of “lifting up” as in Genesis 40:13); as the Targum has it, תקבל. The sense is: when you wish to obtain the sum total of their number — to know how many they are — do not take their census by their polls but each of them shall give half a shekel, and you shall count these, and so ascertain their number.
כי תשא..ונתנו איש כפר נפשו, the need to count human beings stems from the fact that human beings are not the same each time, i.e. ever since death was decreed upon mankind this reflects sin. Prior to sin man, who was meant to live indefinitely, would be the same at each count. The sages have said that no one dies unless he had committed a sin (Shabbat 55). It follows that mention of a head count of people is an oblique reminder of man’s sin, his guilt. This being so, it is most appropriate that at the time of such count he should pay some ransom on behalf of his soul, his life, so that he will qualify for atonement. This also explains why the poor must not give less nor the rich more, as a soul’s ransom is not calculated in terms of the amount of money offered to G’d.
העשיר לא ירבה, “the wealthy person must not contribute more;” (in order to help make up the required total). No one was allowed to be able to claim that he had made a greater contribution to the Tabernacle than his neighbour.
And the Lord spoke unto Moses, saying: “See, I have called by name Bezalel” (Exod. 31:1). Solomon said: Whatsoever cometh into being, the name thereof was given long ago, and it is foreknown what man is (Eccles. 6:10). Scripture also says elsewhere in reference to this: Who hath wrought and done it? He that called the generations from the beginning (Isa. 14:4). The Holy Blessed One, declared: When I determined at the very beginning of time to build the Sanctuary, I already announced his name, and made his name known.
Similarly, Rabbi Yoḥanan said: Three matters are proclaimed by the Holy One, Blessed be He, Himself: Famine, plenty, and a good leader. The Gemara enumerates the sources for these cases: Famine, as it is written: “For the Lord has called for a famine; and it shall also come upon the land seven years” (II Kings 8:1). Plenty, as it is written: “And I will call for the grain, and will increase it, and lay no famine upon you” (Ezekiel 36:29). And a good leader, as it is written: “And the Lord spoke unto Moses, saying: See, I have called by name Bezalel, son of Uri, son of Hur, of the tribe of Judah” (Exodus 31:1–2).
On a similar note, Rabbi Yoḥanan said: The Holy One, Blessed be He, only grants wisdom to one who already possesses wisdom, as it is stated: “He gives wisdom unto the wise, and knowledge to they who know understanding” (Daniel 2:21). Rav Taḥalifa, from the West, Eretz Yisrael, heard this and repeated it before Rabbi Abbahu. Rabbi Abbahu said to him: You learned proof for this idea from there; we learn it from here: As it is written in praise of the builders of the Tabernacle: “And in the hearts of all who are wise-hearted I have placed wisdom” (Exodus 31:6).
The words: "written with the finger of G'd" mean that G'd drew the shape of the letter with His "finger," i.e. using one of the kinds of light at His disposal. It (the light) assumed the appearance of a finger opposite the Tablets corresponding to the dimensions of the requisite letter G'd wanted to inscribe. G'd did this in order to ensure that no more and and no less than the letter should be engraved on the Tablets themselves. Seeing that the light G'd used to do this with was more powerful than the light the Tablets were made of, the light of the "finger" penetrated the requisite area of the Tablets. We may perceive of that area on the Tablets as having either been devoured or pushed aside. What remained were holes forming the letters G'd had engraved. Thanks to the superior power of the light of the "finger" the inscription became visible from either side of the Tablets. This is what is meant when the Torah wrote in 32:16, that the Tablets were written from both sides, i.e. that the inscription was deeply engraved. The Torah uses the expression חרות על הלוחות "engraved on the Tablets," instead of saying חדות בלוחות, engraved in the Tablets. This is the allusion to G'd having placed His finger "on" i.e. opposite the material of the Tablets as we have explained.