We reverse the summary final judgment in favor of appellees, Bernard and Esther Lee, with directions that summary final judgment be entered in favor of the appellants, Irving and Elsie Deich. The Deiches, formerly business partners with the Lees, sold all of their corporate assets to the Lees. The Lees assumed all obligations of the former enterprise and issued a hold harmless agreement in favor of the Deiches. There was no ambiguity in the hold harmless agreement so as to defeat the subsequent promissory note and schedule of payments given by Bernard Lee in favor of Irving Deich when an Internal Revenue Service claim was personally paid and satisfied by Deich. National Health Laboratories, Inc. v. Bailmar, Inc., 444 So.2d 1078 (Fla. 3d DCA 1984), review denied, 453 So.2d 43 (Fla. 1984). Further, Lee’s partial past payment to Deich is entitled to great weight in construction of the various instruments employed by the parties. Lalow v. Codomo, 101 So.2d 390 (Fla. 1958); Spindler v. Kushner, 284 So.2d 481 (Fla. 3d DCA 1973).

Accordingly, the decision of the trial court is reversed and remanded.