I’m fairly surprised nobody brought up the great Judge Gideon.
Sacred Scripture takes no issue with asking for a sign, as illustrated by the story of Gideon and the dew on the fleece.
Judges 6:36-40 (NABRE)
Gideon said to God, “If indeed you are going to save Israel through me, as you have said, 37 I am putting this woolen fleece on the threshing floor, and if dew is on the fleece alone, while all the ground is dry, I shall know that you will save Israel through me, as you have said.” 38 That is what happened. Early the next morning when he wrung out the fleece, he squeezed enough dew from it to fill a bowl. 39 Gideon then said to God, “Do not be angry with me if I speak once more. Let me make just one more test with the fleece. Let the fleece alone be dry, but let there be dew on all the ground.” 40 That is what God did that night: the fleece alone was dry, but there was dew on all the ground.
Some commentary from the Haydock Bible:
Ver. 38. So. Gedeon besought the Lord to confirm his mission, in order to raise the drooping spirits of his soldiers. If he had not believed that he was chosen for the purpose of rescuing Israel, he would never have exposed himself, by destroying the idol and grove of Baal, and by calling the people to arms. Yet he might fear at present, lest he might be destitute of some of the necessary qualifications, and might entertain some apprehensions, lest the promises of God might by only conditional. The readiness with which God grants his requests, shews that he was inspired to act as he did, and his faith is greatly commended, Hebrews xi. 32. Other great saints have asked for a miraculous confirmation of what was promised, Exodus iv. 1., Josue v. 13., and Luke i. 34. (Calmet) — Vessels. Hebrew sephel, Septuagint lecané, “a dish.” Syriac, “a basin.” The dew in Chanaan is very copious, resembling a shower of rain, insomuch that the roads are rendered extremely slippery. (Roger. i. 2.) (Calmet)
Ver. 40. Ground. In these two miracles the Fathers observe, that the fleece represented the Jewish nation, favoured with so many graces, while the rest of the world was dry and barren; and that, when the latter was watered with dew from heaven, by the coming of Jesus Christ, the Synagogue was deprived of those favours. (Origen, hom. viii.; Theodoret, q. 14.; St. Jerome, ad Paulin.; St. Augustine; &c.) — In the first miracle we may also contemplate, the incarnation of our Saviour [Jesus Christ] in the womb of the most pure Virgin [Mary], Psalm lxxi. 6. (St. Bernard, serm.; St. Jerome, epist. Paul.) (Calmet)