The synoptic Gospels,[346] which are primarily devoted to the labors of Christ in Galilee, contain no mention of His attendance at the paschal festival between His twelfth year and the time of His death; to John alone are we indebted for the record of this visit at the beginning of Christ's public ministry. It is not improbable that Jesus had been present at other Passovers during the eighteen years over which the evangelists pass in complete and reverent silence; but at any or all such earlier visits, He, not being thirty years old, could not have assumed the right or privilege of a teacher without contravening established customs.[347] It is worth our attention to note that on this, the first recorded appearance of Jesus in the temple subsequent to His visit as a Boy, He should resume His "Father's business" where He had before been engaged. It was in His Father's service that He had been found in discussion with the doctors of the law,[348] and in His Father's cause He was impelled to action on this later occasion. The multitudinous and mixed attendance at the Passover celebration has already received passing mention;[349] some of the unseemly customs that prevailed are to be held in mind. The law of Moses had been supplemented by a cumulative array of rules, and the rigidly enforced requirements as to sacrifices and tribute had given rise to a system of sale and barter within the sacred precincts of the House of the Lord. In the outer courts were stalls of oxen, pens of sheep, cages of doves and pigeons; and the ceremonial fitness of these sacrificial victims was cried aloud by the sellers, and charged for in full measure. It was the custom also to pay the yearly poll tribute of the sanctuary at this season--the ransom offering required of every male in Israel, and amounting to half a shekel[350] for each, irrespective of his relative poverty or wealth. This was to be paid "after the shekel of the sanctuary," which limitation, as rabbis had ruled, meant payment in temple coin. Ordinary money, varieties of which bore effigies and inscriptions of heathen import, was not acceptable, and as a result, money-changers plied a thriving trade on the temple grounds.