וַיֹּ֨אמֶר לְגֵיחֲזִ֜י חֲגֹ֣ר מָתְנֶ֗יךָ וְקַ֨ח מִשְׁעַנְתִּ֣י בְיָדְךָ֮ וָלֵךְ֒ כִּֽי־תִמְצָ֥א אִישׁ֙ לֹ֣א תְבָרְכֶ֔נּוּ וְכִֽי־יְבָרֶכְךָ֥ אִ֖ישׁ לֹ֣א תַעֲנֶנּ֑וּ וְשַׂמְתָּ֥ מִשְׁעַנְתִּ֖י עַל־פְּנֵ֥י הַנָּֽעַר׃
[Der Prophet] befahl Gehasi: Gürte deine Lenden und nimm meinen Stab in deine Hand und gehe. Wenn du jemand triffst, grüße ihn nicht, und wenn dich jemand grüßt, antworte ihm nicht, und lege meinen Stab auf das Gesicht des Knaben.
Radak
ויברך יעקב את פרעה. He greeted him (bestowed a blessing) as is customary when one is introduced to the king. The custom is highlighted in Kings II 4,29 where Elisha told Gechazi not to respond to anyone’s greeting. Yaakov blessed Pharaoh again upon leaving after the audience. I have not found a satisfactory explanation why the Torah had to report something so ordinary.
Chizkuni
על משענתו, “supporting himself on his walking cane;” the word משענת is used in the Bible in this sense in Kings II 4,29: וקח משענתי בידך, ”and take my walking cane in your hand;” [Elisha speaking to his servant Geychazi)
Rabbeinu Bahya
One reason was in order to conceal the fact that he enjoyed heavenly assists. He did not want the evil eye to interfere with his success. You will find a similar consideration at work when Elisha told his disciple Gechazi (Kings II 4,29) on the mission to resurrect the son of the Shunamite that he should not speak unnecessarily with people whom he would encounter on the way. Gechazi ignored these instructions and even boasted about what he was about to do. The result was that he failed and the boy did not respond to his attempts to awaken him.