First of all, I place my tithe envelope in the offering basket as soon as I enter the sanctuary ( before we start preparing for service). Would it be fair to examine honestly whether your unconsious failure to put it in the basket is due to one of the following- perhaps deep down in your heart you are unsure what you really believe about tithing, or even giving. In that case, I would be searching out the scriptures and seeking God earnestly. My experience is that when I tithe, I dont go without anything I need like shoes,etc. but when I hold back, then my paycheck seems to be like a bucket with holes in it.I cant keep anything and it always seems empty. Also, If I give just so someone sees me give, then that is for me, not for Him.
Secondly, I believe giving is an act of Worship- another way of honoring God and acknowledging Him as my Wonderful Provider. We sing" All that I have comes from Him" Do we really believe that?
Furthermore, Jesus came to FULFILL the law, not Abolish the law. All of the penalty and judgement for our sins was laid on Him. so dont sweat the past, Receive His Grace, but seek Him about how to conduct your finances in the future. Finally, to those who don't believe that Jesus paid tithes, who knows? but I believe since He fullfilled every jot and tittle of the law, He did do so. Otherwise they could have found fault in Him. Also, we know He paid His temple tax, and also gave alms and instructed us to do so ( Matt 6:1-4). It appears that if you are really having a hard time in this issue, God might be wanting you to trust Him more, so I want to encourage you to just Sincerely, Honestly and openly, Seek God about the problem,Ask for a solution,and be obedient, and just know that He loves you!