Hebrews 12:25 Pay careful attention so that you do not refuse to hear God when He speaks to you. See verse. For if those people i.e., the Israelites did not escape judgment when they refused to hear Him who warned them on earth i.e., God speaking through Moses at Mount Sinai, how much less likely will we escape judgment if we reject Him who warns from heaven i.e., Christ?

AUV⁽ⁱ⁾ ²⁵ Pay careful attention so that you do not refuse [to hear] God when He speaks to you. [See verse 9]. For if those people [i.e., the Israelites] did not escape [judgment] when they refused [to hear] Him who warned them on earth [i.e., God speaking through Moses at Mount Sinai], how much less [likely] will we escape [judgment] if we reject Him who warns from heaven [i.e., Christ]?