Or HaChaim on Exodus 28:3/אור החיים על שמות כ״ח:ג׳

1 ואתה תדבר אל כל חכמי לב, "And you are to speak to all wise-hearted men, etc." The reason the Torah introduces this verse with the word ואתה is that Moses was to involve himself personally in speaking to those people. Although G'd had already said: "you are to make the holy garments," G'd repeated instructions to Moses here to make clear that Moses was not personally to make these garments but that they should be made at his behest. If the Torah had not issued instructions for Moses to personally speak to the artisans who were to make the garments, we would have thought that as long as these garments were made according to Moses' instructions it would not matter if he had personally charged the artisans with their task.

2The Torah is careful to say אל כל חכמי לב, "to all the wise-hearted men," as the fact that Moses would take out time to speak to all of them individually would be one of the signs demonstrating that he was personally anxious that Aaron be provided with such splendid robes. Had he not been enthusiastic about this task, Moses would have delegated as much of this task as he could and would certainly not have addressed every single artisan who was active in their construction.

3Furthermore, the reason that the Torah employs the word ואתה no less than three times in these five verses is a sign that Moses would enjoy the merit of performing three distinct services in connection with the building of the Tabernacle. He would receive credit for a) issuing the instructions to bring the donations enabling the Tabernacle to be built; b) for the overall instructions for building Tabernacle including its furnishings and the priestly garments; c) for the service that would be performed in the Holy Tabernacle as a result of his being instrumental in the Tabernacle being built. This was one of the reasons G'd said that the Israelites were to take things to him, or to bring things to him, or why he was to speak personally to all the wise-hearted men. All of this made Moses a messenger of the people. It would therefore be accounted for him as if he himself had performed every single activity connected with the project. The instruction to bring Aaron close to himself meant that when Aaron would perform the Temple service he would also do so as Moses' messenger. This is why the Torah was careful to write: אליך, "to you." The above-mentioned considerations also account for G'd' issuing these instructions to Moses in direct speech rather than in the third person describing what the individuals who actually fashioned the Tabernacle and its furnishings were to do. G'd meant for Moses to issue directives for others to carry out the work.