Jewish tradition understands the nation of Israel to be 'yoked' to the Law (Song 1.10). But most people don't recognize that these ancient yokes were shaped like crosses. This understanding was certainly core to the original gospel writer. He must have witnessed a crucifixion - maybe many crucifixions - and hit upon the symbolism.
All these the fear inspired by the law,— leading as a pædagogue to Christ, trained so as to manifest their piety by their blood. God stood in the congregation of the gods; He judges in the midst of the gods. Who are they? Those that are superior to Pleasure, who rise above the passions, who know what they do— the Gnostics, who are greater than the world. I said, You are Gods; and all sons of the Highest. To whom speaks the Lord? To those who reject as far as possible all that is of man. And the apostle says, For you are not any longer in the flesh, but in the Spirit. (Romans 8:9) And again he says, Though in the flesh, we do not war after the flesh. (2 Corinthians 10:3) For flesh and blood cannot inherit the kingdom of God, neither does corruption inherit incorruption. (1 Corinthians 15:50) Lo, you shall die like men, the Spirit has said, confuting us. We must then exercise ourselves in taking care about those things which fall under the power of the passions, fleeing like those who are truly philosophers such articles of food as excite lust, and dissolute licentiousness in chambering and luxury; and the sensations that tend to luxury, which are a solid reward to others, must no longer be so to us. For God's greatest gift is self-restraint. For He Himself has said, I will neyer leave you, nor forsake you, Hebrews 13:5 as having judged you worthy according to the true election. Thus, then, while we attempt piously to advance, we shall have put on us the mild yoke of the Lord (ὁ χρηστὸς τοῦ κυρίου ζυγός) from faith to faith, one charioteer driving each of us onward to salvation, that the meet fruit of beatitude may be won. (Stromata 2.20)